Journal articles: 'Peptide/antigen'

1

Tam, James P., and Fidel Zavala. "Multiple antigen peptide." Journal of Immunological Methods 124, no. 1 (1989): 53–61. http://dx.doi.org/10.1016/0022-1759(89)90185-3.

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TAKIGUCHI, MASAFUMI. "HLA AND ANTIGEN PEPTIDE." Vox Sanguinis 70, S3 (1996): 102–10. http://dx.doi.org/10.1111/j.1423-0410.1996.tb01380.x.

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Marusina, Kate, and John J. Monaco. "Peptide transport in antigen presentation." Current Opinion in Hematology 3, no. 1 (1996): 19–26. http://dx.doi.org/10.1097/00062752-199603010-00004.

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4

Adorini, Luciano, and Zoltan A. Nagy. "Peptide competition for antigen presentation." Immunology Today 11 (January 1990): 21–24. http://dx.doi.org/10.1016/0167-5699(90)90006-u.

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de Kroon, A. I., and H. M. McConnell. "Enhancement of peptide antigen presentation by a second peptide." Proceedings of the National Academy of Sciences 90, no. 19 (1993): 8797–801. http://dx.doi.org/10.1073/pnas.90.19.8797.

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Watts, T. H., J. Gariepy, G. K. Schoolnik, and H. M. McConnell. "T-cell activation by peptide antigen: effect of peptide sequence and method of antigen presentation." Proceedings of the National Academy of Sciences 82, no. 16 (1985): 5480–84. http://dx.doi.org/10.1073/pnas.82.16.5480.

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Tran, Phat, Jonathan Kopel, Joe A. Fralick, and Ted W. Reid. "The Use of an Organo-Selenium Peptide to Develop New Antimicrobials That Target a Specific Bacteria." Antibiotics 10, no. 6 (2021): 611. http://dx.doi.org/10.3390/antibiotics10060611.

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This study examines the use of a covalently selenium-bonded peptide and phage that binds to the Yersinia pestis F1 antigen for the targeting and killing of E. coli expressing this surface antigen. Using a Ph.D.-12 phage-display library for affinity selection of the phage which would bind the F1 antigen of Y. pestis, a phage displaying a peptide that binds the F1 antigen with high affinity and specificity was identified. Selenium was then covalently attached to the display phage and the corresponding F1-antigen-binding peptide. Both the phage and peptides with selenium covalently attached retained their binding specificity for the Y. pestis F1 antigen. The phage or peptide not labeled with selenium did not kill the targeted bacteria, while the phage or peptide labeled with selenium did. In addition, the seleno-peptide, expressing the F1 targeting sequence only, killed cells expressing the F1 antigen but not the parent strain that did not express the F1 antigen. Specifically, the seleno-peptide could kill eight logs of bacteria in less than two hours at a 10-µM concentration. These results demonstrate a novel approach for the development of an antibacterial agent that can target a specific bacterial pathogen for destruction through the use of covalently attached selenium and will not affect other bacteria.

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Huang, Wolin, Bernardetta Nardelli, and James P. Tam. "Lipophilic multiple antigen peptide system for peptide immunogen and synthetic vaccine." Molecular Immunology 31, no. 15 (1994): 1191–99. http://dx.doi.org/10.1016/0161-5890(94)90033-7.

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Coles, Charlotte H., Catriona McMurran, Angharad Lloyd, et al. "T cell receptor interactions with human leukocyte antigen govern indirect peptide selectivity for the cancer testis antigen MAGE-A4." Journal of Biological Chemistry 295, no. 33 (2020): 11486–94. http://dx.doi.org/10.1074/jbc.ra120.014016.

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T cell-mediated immunity is governed primarily by T cell receptor (TCR) recognition of peptide-human leukocyte antigen (pHLA) complexes and is essential for immunosurveillance and disease control. This interaction is generally stabilized by interactions between the HLA surface and TCR germline-encoded complementarity-determining region (CDR) loops 1 and 2, whereas peptide selectivity is guided by direct interactions with the TCR CDR3 loops. Here, we solved the structure of a newly identified TCR in complex with a clinically relevant peptide derived from the cancer testis antigen melanoma antigen-A4 (MAGE-A4). The TCR bound pHLA in a position shifted toward the peptide's N terminus. This enabled the TCR to achieve peptide selectivity via an indirect mechanism, whereby the TCR sensed the first residue of the peptide through HLA residue Trp-167, which acted as a tunable gateway. Amino acid substitutions at peptide position 1 predicted to alter the HLA Trp-167 side-chain conformation abrogated TCR binding, indicating that this indirect binding mechanism is essential for peptide recognition. These findings extend our understanding of the molecular rules that underpin antigen recognition by TCRs and have important implications for the development of TCR-based therapies.

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Van Kaer, Luc. "Antigen Presentation: Discovery of the Peptide TAP." Journal of Immunology 180, no. 5 (2008): 2723–24. http://dx.doi.org/10.4049/jimmunol.180.5.2723.

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Unanue, Emil R. "From antigen processing to peptide-MHC binding." Nature Immunology 7, no. 12 (2006): 1277–79. http://dx.doi.org/10.1038/ni1206-1277.

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Bielekova, Bibiana, and Roland Martin. "Antigen-specific immunomodulation via altered peptide ligands." Journal of Molecular Medicine 79, no. 10 (2001): 552–65. http://dx.doi.org/10.1007/s001090100259.

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Barnes, K. A., and R. N. Mitchell. "Detection of functional class II-associated antigen: role of a low density endosomal compartment in antigen processing." Journal of Experimental Medicine 181, no. 5 (1995): 1715–27. http://dx.doi.org/10.1084/jem.181.5.1715.

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We have developed a functional assay to identify processed antigen in subcellular fractions from antigen-presenting cells; stimulatory activity in this assay may be caused by either free peptide fragments or by complexes of peptide fragments and class II molecules present on organellar membrane sheets and vesicles. In addition, we have developed a functional assay to identify proteolytic activity in subcellular fractions capable of generating antigenic peptides from intact proteins. These techniques permit the direct identification of intracellular sites of antigen processing and class II association. Using a murine B cell line stably transfected with a phosphorylcholine (PC)-specific membrane-bound immunoglobulin (Ig), we show that PC-conjugated antigens are rapidly internalized and efficiently degraded to generate processed antigen within an early low density compartment. Proteolytic activity capable of generating antigenic peptide fragments from intact proteins is found within low density endosomes and a dense compartment consistent with lysosomes. However, neither processed peptide nor peptide-class II complexes are detected in lysosomes from antigen-pulsed cells. Furthermore, blocking the intracellular transport of internalized antigen from the low density endosome to lysosomes does not inhibit the generation of processed antigen. Therefore, antigens internalized in association with membrane Ig on B cells can be efficiently processed in low density endosomal compartments without the contribution of proteases present within denser organelles.

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Kedl, Ross M., William A. Rees, David A. Hildeman, et al. "T Cells Compete for Access to Antigen-Bearing Antigen-Presenting Cells." Journal of Experimental Medicine 192, no. 8 (2000): 1105–14. http://dx.doi.org/10.1084/jem.192.8.1105.

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These studies tested whether antigenic competition between T cells occurs. We generated CD8+ T cell responses in H-2b mice against the dominant ovalbumin epitope SIINFEKL (ova8) and subdominant epitope KRVVFDKL, using either vaccinia virus expressing ovalbumin (VV-ova) or peptide-pulsed dendritic cells. CD8+ T cell responses were visualized by major histocompatibility complex class I–peptide tetrameric molecules. Transfer of transgenic T cells with high affinity for ova8 (OT1 T cells) completely inhibited the response of host antigen-specific T cells to either antigen, demonstrating that T cells can directly compete with each other for response to antigen. OT1 cells also inhibited CD8+ T cell responses to an unrelated peptide, SIYRYGGL, providing it was presented on the same dendritic cells as ova8. These inhibitions were not due to a more rapid clearance of virus or antigen-presenting cells (APCs) by the OT1 cells. Rather, the inhibition was caused by competition for antigen and antigen-bearing cells, since it could be overcome by the injection of large numbers of antigen-pulsed dendritic cells. These results imply that common properties of T cell responses, such as epitope dominance and secondary response affinity maturation, are the result of competitive interactions between antigen-bearing APC and T cell subsets.

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Traversari, C., P. van der Bruggen, I. F. Luescher, et al. "A nonapeptide encoded by human gene MAGE-1 is recognized on HLA-A1 by cytolytic T lymphocytes directed against tumor antigen MZ2-E." Journal of Experimental Medicine 176, no. 5 (1992): 1453–57. http://dx.doi.org/10.1084/jem.176.5.1453.

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We have reported the identification of human gene MAGE-1, which directs the expression of an antigen recognized on a melanoma by autologous cytolytic T lymphocytes (CTL). We show here that CTL directed against this antigen, which was named MZ2-E, recognize a nonapeptide encoded by the third exon of gene MAGE-1. The CTL also recognize this peptide when it is presented by mouse cells transfected with an HLA-A1 gene, confirming the association of antigen MZ2-E with the HLA-A1 molecule. Other members of the MAGE gene family do not code for the same peptide, suggesting that only MAGE-1 produces the antigen recognized by the anti-MZ2-E CTL. Our results open the possibility of immunizing HLA-A1 patients whose tumor expresses MAGE-1 either with the antigenic peptide or with autologous antigen-presenting cells pulsed with the peptide.

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Kariyone, Ai, Kazue Higuchi, Shigeki Yamamoto та ін. "Identification of Amino Acid Residues of the T-Cell Epitope of Mycobacterium tuberculosis α Antigen Critical for Vβ11+ Th1 Cells". Infection and Immunity 67, № 9 (1999): 4312–19. http://dx.doi.org/10.1128/iai.67.9.4312-4319.1999.

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ABSTRACT Stimulation of Mycobacterium tuberculosis-primed lymph node cells from C57BL/6 mice with α antigen (also known as antigen 85B and MPT59) induced cell proliferation, production of interleukin 2 and gamma interferon, and expansion of Vβ11+CD4+ T cells in conjunction with antigen-presenting cells in an I-Ab-restricted manner. Using a series of 15-amino-acid peptides that overlapped each other by 5 amino acids and spanned the mature α antigen, we identified the antigenic epitope for α antigen-specific Vβ11+ Th1 cells. That peptide (peptide-25), which corresponds to amino acid residues 240 to 254 of α antigen, contains a motif that is conserved in I-Ab and requires processing by antigen-presenting cells. Using peptide-25-reactive Vβ11+ T-cell clones and substituted peptide-25 mutants, we determined which amino acid residues within peptide-25 were critical for T-cell receptor (TCR) recognition. Our results showed that the amino acid residues at positions 245, 246, 248, 250, and 251 are important for recognition of TCRVβ11 and that residues at positions 244, 247, 249, and 252 are I-Abcontact residues. We also observed that active immunization of C57BL/6 mice with peptide-25 can lead to decreased bacterial load in the lungs of M. tuberculosis H37Rv-infected mice. These results should provide us with a useful tool for delineating the regulation of Vβ11+ Th1-cell development during M. tuberculosis infection and for developing a vaccine inducing a Th1-dominant immune response.

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Bae, Jooeun, Parayath Neha, Mansoor Amiji, Nikhil Munshi, and Kenneth Anderson. "Bcma Heteroclitic Peptide Encapsulated Nanoparticle Enhances Antigen Stimulatory Capacity and Tumor-Specific CD8+ cytotoxic T Lymphocytes Against Multiple Myeloma." Blood 132, Supplement 1 (2018): 3195. http://dx.doi.org/10.1182/blood-2018-99-117292.

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Abstract Background: B-cell Maturation Antigen (BCMA), a member of the tumor necrosis factor (TNF) receptor superfamily and the receptor for binding of B cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL), is a promising therapeutic target for MM. Due to its restricted expression pattern on MM cells and plasma cells along with its role in promoting MM cells growth, survival, and drug resistance, BCMA is being targeted by several immunotherapeutic strategies including antibodies, immunotoxins, bispecific T-cell engagers, and CAR-T cells. Recently, we have identified nanomedicine-based therapeutics targeting BCMA as a promising area of translational research to effectively evoke and augment anti-tumor responses in MM patients. Several nanomedicines are available and more advanced nanoparticle constructs are under development for antigen encapsulation. To this end, we have designed a heteroclitic BCMA peptide encapsulated nanoparticle-based cancer vaccine to overcome the limitations of free peptide vaccines including poor peptide stability, susceptibility to enzyme degradation, and low antigen uptake and delivery. Furthermore, the nanotechnology-based cancer vaccine was developed to induce more robust BCMA-specific CD8+ cytotoxic T lymphocytes (CTL) activities in MM patients, with more sustained antigen release and increased bioavailability and presentation of the immunogenic peptide. Here, we examine the potential of a novel nanomedicine-based therapeutic delivery system specific to BCMA antigen to treat the patients with MM. Objective: The purpose of this study was to design the optimal nanoparticle encapsulated BCMA antigen constructs to efficiently evoke and develop the BCMA-specific CD8+ CTL with functional anti-myeloma activities. Findings: Nanoparticles [liposome or poly(D,L-lactide-co-glycolide) (PLGA)] with different antigen-release kinetics demonstrated their capacity to effectively deliver heteroclitic BCMA peptideto antigen-presenting cells and evoke BCMA antigen-specific CTL with anti-MM activities. The heteroclitic BCMA peptide encapsulated nanoparticles demonstrated a higher uptake by human dendritic cells than free peptide, with the highest uptake mediated with liposome-based nanoparticles. In contrast, BCMA-specific CTL induced with PLGA-based nanoparticle demonstrated the highest functional activities and specific immune responses against MM cells. The PLGA/BCMA peptide nanoparticle induced BCMA-specific CTL displayed the highest increases in CD107a degranulation, the antigen-specific CD8+ T cells proliferation and Th-1 type cytokines (IFN-g, IL-2, TNF-a) production to MM patients' tumor cells and MM cell lines compared to BCMA-CTL generated with free BCMA peptide or liposome/BCMA peptide nanoparticle. These observations were aligned with the highest level of CD28 costimulatory molecules upregulation, Tetramer+ CTL generation and peptide-specific responses within the BCMA-CTL generated by PLGA/BCMA nanoparticles. Furthermore, the PLGA/BCMA nanoparticles triggered a more robust induction of antigen-specific memory CD8+ T cells, which demonstrated significantly higher anti-tumor activities, evidenced by CD107a degranulation and IFN-g production, compared to non-memory CD8+ T cells within the BCMA-CTL. Especially, the increased central memory CTL development and their anti-tumor activities evoked by PLGA/BCMA peptide were associated with the optimal peptide release kinetics and enhanced immunogenicity of the antigen via this nanotechnology. Thus, these results demonstrate that the heteroclitic BCMA peptide encapsulated nanoparticle strategy supports the peptide delivery into dendritic cells and then subsequently to T cells, resulting in effective induction of BCMA-specific central memory CTL with poly-functional activities against MM. Significance: These results demonstrate the utility of nanotechnology using encapsulated heteroclitic BCMA peptide to enhance the immunogenicity of BCMA peptide-specific therapeutics against MM. Importantly, our observations provide the framework for therapeutic application of PLGA-based heteroclitic BCMA peptide delivery to enhance the BCMA-specific memory T cell immune responses, overcome the limitations of current peptide-based cancer vaccine, and improve the patient outcome in MM. Disclosures Munshi: OncoPep: Other: Board of director. Anderson:Bristol Myers Squibb: Consultancy; Celgene: Consultancy; Millennium Takeda: Consultancy; C4 Therapeutics: Equity Ownership, Other: Scientific founder; OncoPep: Equity Ownership, Other: Scientific founder; Gilead: Membership on an entity's Board of Directors or advisory committees.

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Eken, Ahmet, Vivian Ortiz, and Jack R. Wands. "Ethanol Inhibits Antigen Presentation by Dendritic Cells." Clinical and Vaccine Immunology 18, no. 7 (2011): 1157–66. http://dx.doi.org/10.1128/cvi.05029-11.

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ABSTRACTPrevious studies suggest that altered virus-specific T-cell responses observed during chronic ethanol exposure may be due to abnormal functioning of dendritic cells (DCs). Here we explored the effects of ethanol on exogenous antigen presentation by DCs. BALB/c, C57BL/6, and CBA/caj mice were fed ethanol or an isocaloric control diet for 8 weeks. The splenic DC population was expanded using an Flt3L expression plasmid via tail vein injection. DCs were purified and assessed for antigen presentation and processing and for peptide-major histocompatibility complex class I and II (MHCI and MHCII) formation on the cell surface. Interleukin-2 (IL-2) was measured as an indicator of antigen-specific T-cell activation by DCs in coculture. Antigen processing and peptide-MHCII complexes were evaluated by flow cytometry. We observed that ethanol not only suppressed allogeneic peptide presentation to T cells by DCs but also altered presentation of exogenous ovalbumin (OVA) peptide 323-339 to an OVA-specific DO11 T-cell line as well as to OVA-sensitized primary T cells. Smaller amounts of peptide-MHCII complexes were found on the DCs isolated from the spleens of ethanol-fed mice. In contrast to MHCII presentation, cross-presentation of exogenous OVA peptide via MHCI by DCs remained intact. More importantly, ethanol-exposed DCs had reduced B7-DC and enhanced ICOS-L (inhibitory) costimulatory molecule expression. Ethanol inhibits exogenous and allogeneic antigen presentation and affects the formation of peptide-MHCII complexes, as well as altering costimulatory molecule expression on the cell surface. Therefore, DC presentation of peptides in a favorable costimulatory protein environment is required to subsequently activate T cells and appears to be a critical target for the immunosuppressive effects of ethanol.

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LaSalle, J. M., P. J. Tolentino, G. J. Freeman, L. M. Nadler, and D. A. Hafler. "Early signaling defects in human T cells anergized by T cell presentation of autoantigen." Journal of Experimental Medicine 176, no. 1 (1992): 177–86. http://dx.doi.org/10.1084/jem.176.1.177.

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Major histocompatibility complex class II-positive human T cell clones are nontraditional antigen-presenting cells (APCs) that are able to simultaneously present and respond to peptide or degraded antigen, but are unable to process intact protein. Although T cell presentation of peptide antigen resulted in a primary proliferative response, T cells that had been previously stimulated by T cells presenting antigen were completely unresponsive to antigen but not to interleukin 2 (IL-2). In contrast, peptide antigen presented by B cells or DR2+ L cell transfectants resulted in T cell activation and responsiveness to restimulation. The anergy induced by T cell presentation of peptide could not be prevented by the addition of either autologous or allogeneic B cells or B7+ DR2+ L cell transfectants, suggesting that the induction of anergy could occur in the presence of costimulation. T cell anergy was induced within 24 h of T cell presentation of antigen and was long lasting. Anergized T cells expressed normal levels of T cell receptor/CD3 but were defective in their ability to release [Ca2+]i to both alpha CD3 and APCs. Moreover, anergized T cells did not proliferate to alpha CD2 monoclonal antibodies or alpha CD3 plus phorbol myristate acetate (PMA), nor did they synthesize IL-2, IL-4, or interferon gamma mRNA in response to either peptide or peptide plus PMA. In contrast, ionomycin plus PMA induced both normal proliferative responses and synthesis of cytokine mRNA, suggesting that the signaling defect in anergized cells occurs before protein kinase C activation and [Ca2+]i release.

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Davis, C. B., J. M. Buerstedde, D. J. McKean, P. P. Jones, H. O. McDevitt, and D. C. Wraith. "The role of polymorphic I-Ak beta chain residues in presentation of a peptide from myelin basic protein." Journal of Experimental Medicine 169, no. 6 (1989): 2239–44. http://dx.doi.org/10.1084/jem.169.6.2239.

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Proteins encoded by genes in the MHC are highly polymorphic. For class II proteins the highest level of polymorphism is found in distinct regions of variability, notably in the membrane-distal domains. To investigate the role of such residues in antigen presentation, we have tested cells transfected with wild-type or mutant I-Ak beta chains for their ability to present the NH2-terminal peptide of myelin basic protein to a panel of T cell clones. We were unable to detect a gross effect on peptide binding, in that all of the mutant cell lines presented antigen to at least one of the cloned T cells. However, the results imply that the more NH2-terminal residues, particularly 12 and 14, are involved in peptide interactions. Mutations at these residues presented antigen only at high antigen concentrations. Furthermore, residues of the more COOH-terminal regions appear to determine TCR interactions. Mutations in the predicted alpha-helical regions of the beta chain affected antigen presentation without abolishing peptide binding.

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Olsson, Ida, Mohamed Eltahir, and Sara Mangsbo. "842 A novel agonistic anti-CD40 targeting strategy with an affinity peptide binding feature for antigen cargo functionality: improving peptide stability and T cell proliferation." Journal for ImmunoTherapy of Cancer 8, Suppl 3 (2020): A894. http://dx.doi.org/10.1136/jitc-2020-sitc2020.0842.

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BackgroundTo induce a prominent anti-tumor T-cell response, a viral or tumor derived antigen epitope imbedded in a longer synthetic peptide (SLP) can be used, which also requires internalization and processing by antigen presenting cells (APCs) to enable T cell priming. Herein we present the design and evaluation of a CD40 targeting tetravalent bispecific antibody, binding peptides through affinity as an antibody-drug conjugate. APC activation as well as in vitro and in vivo T-cell proliferation studies demonstrate retained agonistic activity as well as improved T cell proliferation/expansion in vitro and in vivo, compared to non-linked peptide/antibody mixes.MethodsT-cell priming was evaluated with B3Z assay or a cytomegalovirus (CMV) model and displayed superior uptake to non-bound peptide in the co-stimulatory independent B3Z assay. In addition, intracellular peptide release in APCs was analysed using a unique quenching strategy displaying peptide release after around 4-6 hour post antigen.ResultsPeptide stability in vitro, when bound to the antibody, was analysed by mass spectrometry and displayed prolonged peptide stability in serum, increasing the peptide half-life by 15 times in vitro (ConclusionsData support that the novel delivery system can improve antigen targeting to dendritic cells, but can also provide a prolonged peptide half-life as well as a peptide delivery to APCs. Combined this improves the efficiency of both antigen delivery and CD40 agonistic functionality.

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Ingulli, Elizabeth, Anna Mondino, Alexander Khoruts, and Marc K. Jenkins. "In Vivo Detection of Dendritic Cell Antigen Presentation to CD4+ T Cells." Journal of Experimental Medicine 185, no. 12 (1997): 2133–41. http://dx.doi.org/10.1084/jem.185.12.2133.

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Although lymphoid dendritic cells (DC) are thought to play an essential role in T cell activation, the initial physical interaction between antigen-bearing DC and antigen-specific T cells has never been directly observed in vivo under conditions where the specificity of the responding T cells for the relevant antigen could be unambiguously assessed. We used confocal microscopy to track the in vivo location of fluorescent dye-labeled DC and naive TCR transgenic CD4+ T cells specific for an OVA peptide–I-Ad complex after adoptive transfer into syngeneic recipients. DC that were not exposed to the OVA peptide, homed to the paracortical regions of the lymph nodes but did not interact with the OVA peptide-specific T cells. In contrast, the OVA peptide-specific T cells formed large clusters around paracortical DC that were pulsed in vitro with the OVA peptide before injection. Interactions were also observed between paracortical DC of the recipient and OVA peptide-specific T cells after administration of intact OVA. Injection of OVA peptide-pulsed DC caused the specific T cells to produce IL-2 in vivo, proliferate, and differentiate into effector cells capable of causing a delayed-type hypersensitivity reaction. Surprisingly, by 48 h after injection, OVA peptide-pulsed, but not unpulsed DC disappeared from the lymph nodes of mice that contained the transferred TCR transgenic population. These results demonstrate that antigen-bearing DC directly interact with naive antigen-specific T cells within the T cell–rich regions of lymph nodes. This interaction results in T cell activation and disappearance of the DC.

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Miñana, Gema, Rafael de la Espriella, Anna Mollar, et al. "Factors associated with plasma antigen carbohydrate 125 and amino-terminal pro-B-type natriuretic peptide concentrations in acute heart failure." European Heart Journal: Acute Cardiovascular Care 9, no. 5 (2020): 437–47. http://dx.doi.org/10.1177/2048872620908033.

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Background: Plasma amino-terminal pro-B-type natriuretic peptide and antigen carbohydrate 125 levels are positively associated with a higher risk of adverse clinical outcomes in acute heart failure. As a proxy of congestion, antigen carbohydrate 125 has also been proposed as a right-sided heart failure marker. Thus, we aimed to determine in this population the main factors – including echocardiographic right-sided heart failure parameters – associated with antigen carbohydrate 125 and amino-terminal pro-B-type natriuretic peptide. Methods and results: We prospectively included 2949 patients admitted with acute heart failure. Amino-terminal pro-B-type natriuretic peptide and antigen carbohydrate 125 were used as dependent variables in a multivariable linear regression analysis. The mean age of the sample was 73.9±11.1 years; 48.9% were female, 35.8% showed ischaemic aetiology, and 51.6% exhibited heart failure with preserved ejection fraction. The median (interquartile range) for amino-terminal pro-B-type natriuretic peptide and antigen carbohydrate 125 were 4840 (2111–9204) pg/ml and 58 (26–129) U/ml, respectively. In a multivariable setting, and ranked in order of importance (R2), estimated glomerular filtration rate (43.7%), left ventricle ejection fraction (15.1%), age (12.4%) and high-sensitivity troponin T (10.9%) emerged as the most important factors associated with amino-terminal pro-B-type natriuretic peptide. The five main factors associated with antigen carbohydrate 125 were, in order of importance: the presence of pleural effusion (36.8%), tricuspid regurgitation severity (25.1%), age (11.9%), amino-terminal pro-B-type natriuretic peptide (6.5%) and peripheral oedema (4.3%). Conclusion: In patients with acute heart failure the main factors associated with amino-terminal pro-B-type natriuretic peptide were renal dysfunction, left ventricle ejection fraction and age. For antigen carbohydrate 125, clinical parameters of congestion and the severity of tricuspid regurgitation were the most important predictors. These results endorse the value of antigen carbohydrate 125 as a useful marker of right-sided heart failure.

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Schmidt, W., M. Buschle, W. Zauner, et al. "Cell-free tumor antigen peptide-based cancer vaccines." Proceedings of the National Academy of Sciences 94, no. 7 (1997): 3262–67. http://dx.doi.org/10.1073/pnas.94.7.3262.

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Urionabarrenetxea, Ainhoa Gonzalez, Robin Fahraeus, Ted Hupp, and Kathryn Ball. "Neo-antigen peptide vaccines as emerging cancer therapeutics." Biochemist 41, no. 1 (2019): 16–21. http://dx.doi.org/10.1042/bio04101016.

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Aging-related diseases, including cancer, will form the major socio-economic health burdens of Western societies this coming century. Enormous expenditure on innovative technologies including combinatorial chemistry, whole genome sequencing, crystallography, high-throughput drug screening and computational science have generated significant advances in understanding the molecular basis of cancer. These advances have rapidly generated hundreds of promising drug leads to key oncogenic targets. However, despite this increased expenditure and research and development (R&D), the number of effective drugs reaching the clinic is in steady decline. There are many possible explanations for this, including political and infrastructure drag. A technical problem is the lack of robust age-dependent, sporadic immune-competent models of human cancer that predict toxicity and response in patients. An ideological hurdle is that, until recently, we have had to use ‘models’ of cancer, such as yeast, worms and flies to identify druggable targets. These models reflect features of a cancer cell but do not mimic tumour tissue in vivo. It is difficult to experimentally model an actual tumour. A tumour could be considered a tissue that includes cancer cells themselves, normal supporting tissue including nutrient conduits, a complex local environment that could be very low in oxygen and many types of immune cells that carry out diverse functions.

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Mahajan, Babita, Jay A. Berzofsky, Robert A. Boykins, et al. "Multiple Antigen Peptide Vaccines against Plasmodium falciparum Malaria." Infection and Immunity 78, no. 11 (2010): 4613–24. http://dx.doi.org/10.1128/iai.00533-10.

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ABSTRACT The multiple antigen peptide (MAP) approach is an effective method to chemically synthesize and deliver multiple T-cell and B-cell epitopes as the constituents of a single immunogen. Here we report on the design, chemical synthesis, and immunogenicity of three Plasmodium falciparum MAP vaccines that incorporated antigenic epitopes from the sporozoite, liver, and blood stages of the life cycle. Antibody and cellular responses were determined in three inbred (C57BL/6, BALB/c, and A/J) strains, one congenic (HLA-A2 on the C57BL/6 background) strain, and one outbred strain (CD1) of mice. All three MAPs were immunogenic and induced both antibody and cellular responses, albeit in a somewhat genetically restricted manner. Antibodies against MAP-1, MAP-2, and MAP-3 had an antiparasite effect that was also dependent on the mouse major histocompatibility complex background. Anti-MAP-1 (CSP-based) antibodies blocked the invasion of HepG2 liver cells by P. falciparum sporozoites (highest, 95.16% in HLA-A2 C57BL/6; lowest, 11.21% in BALB/c). Furthermore, antibodies generated following immunizations with the MAP-2 (PfCSP, PfLSA-1, PfMSP-142, and PfMSP-3b) and MAP-3 (PfRAP-1, PfRAP-2, PfSERA, and PfMSP-142) vaccines were able to reduce the growth of blood stage parasites in erythrocyte cultures to various degrees. Thus, MAP-based vaccines remain a viable option to induce effective antibody and cellular responses. These results warrant further development and preclinical and clinical testing of the next generation of candidate MAP vaccines that are based on the conserved protective epitopes from Plasmodium antigens that are widely recognized by populations of divergent HLA types from around the world.

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Thomas, David W., Maxine J. Solvay, Gregg Hadley, Soraya Betancourt, Susie Jun, and Roderick Nairn. "Functional and biochemical parameters of peptide antigen presentation." Cellular Immunology 113, no. 2 (1988): 387–403. http://dx.doi.org/10.1016/0008-8749(88)90036-6.

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Chen, Swey-Shen, Robert Schmaltz, Yan-Yu Wang, et al. "Inhibition of Antigen-Specific IgE Production by Antigen Coupled to Membrane IgE Peptide." Immunological Investigations 25, no. 5-6 (1996): 495–505. http://dx.doi.org/10.3109/08820139609055738.

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Aichele, P., K. Brduscha-Riem, S. Oehen, R. M. Zinkernagel, H. Hengartner, and H. Pircher. "Peptide-antigen treatment of naive and memory CTL: Antigen-specific tolerization versus immunopathology." Immunology Letters 56 (May 1997): 34. http://dx.doi.org/10.1016/s0165-2478(97)85130-9.

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Aichele, P. "Peptide-antigen treatment of naive and memory CTL: Antigen-specific tolerization versus immunopathology." Immunology Letters 56, no. 1-3 (1997): 34. http://dx.doi.org/10.1016/s0165-2478(97)86968-4.

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Katakura, Yoshio, Takahiro Miyazaki, Hitomi Wada, et al. "Control of antibody–antigen interaction using anion-induced conformational change in antigen peptide." Protein Engineering, Design and Selection 13, no. 10 (2000): 719–24. http://dx.doi.org/10.1093/protein/13.10.719.

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Silva-Flannery, Luciana M., Monica Cabrera-Mora, Megan Dickherber, and Alberto Moreno. "Polymeric Linear Peptide Chimeric Vaccine-Induced Antimalaria Immunity Is Associated with Enhanced In Vitro Antigen Loading." Infection and Immunity 77, no. 5 (2009): 1798–806. http://dx.doi.org/10.1128/iai.00470-08.

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ABSTRACT Immunization of mice with Plasmodium berghei or Plasmodium yoelii synthetic linear peptide chimeras (LPCs) based on the circumsporozoite protein protects against experimental challenge with viable sporozoites. The immunogenicity of LPCs is significantly enhanced by spontaneous polymerization. To better understand the antigenic properties of polymeric antimalarial peptides, we studied the immune responses elicited in mice immunized with a polymer or a monomer of a linear peptide construct specific for P. yoelii and compared the responses of antigen-presenting cells following incubation with both peptide species. Efficient uptake of the polymeric peptide in vitro resulted in higher expression of the coactivation markers CD80, CD40, and CD70 on dendritic cells and higher proinflammatory cytokine production than with the monomeric peptide. Macropinocytosis seems to be the main route used by polymeric peptides internalized by antigen-presenting cells. Spontaneous polymerization of synthetic antimalarial-peptide constructs to target professional antigen-presenting cells shows promise for simple delivery of subunit malaria vaccines.

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Oehen, S., L. Feng, Y. Xia, C. D. Surh, and S. M. Hedrick. "Antigen compartmentation and T helper cell tolerance induction." Journal of Experimental Medicine 183, no. 6 (1996): 2617–26. http://dx.doi.org/10.1084/jem.183.6.2617.

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The process of antigen recognition depends in part on the amount of peptide antigen available and the affinity of the T cell receptor for a particular peptide-major histocompatibility complex (MHC) molecule complex. The availability of self antigen is limited by antigen processing, which is compartmentalized such that peptide antigens presented by MHC class I molecules originate in the cytoplasm, whereas peptide antigens presented by MHC class II molecules are acquired from the endocytic pathway. This segregation of the antigen-processing pathways may limit the diversity of antigens that influence the development and selection of, e.g., CD4-positive, MHC class II-specific T cells. Selection in this case might involve only a subset of self-encoded proteins, specifically those that are plasma membrane bound or secreted. To study these aspects of immune development, we engineered pigeon cytochrome for expression in transgenic mice in two forms: one in which it was expressed as a type II plasma membrane protein, and a second in which it was targeted to the mitochondria after cytoplasmic synthesis. Experiments with these mice clearly show that tolerance is induced in the thymus, irrespective of antigen compartmentation. Using radiation bone marrow chimeras, we further show that cytoplasmic/mitochondrial antigen gains access to the MHC class II pathway by direct presentation. As a result of studying the anatomy of the thymus, we show that the amount of antigen and the affinity of the TCR affect the location and time point of thymocytes under-going apoptosis.

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Brown, Matthew E., Haixi Miao, and Mark D. McKee. "Recognition of Carcinoembryonic Antigen Peptide and Heteroclitic Peptide by Peripheral Blood T Lymphocytes." Journal of Immunotherapy 30, no. 3 (2007): 350–58. http://dx.doi.org/10.1097/cji.0b013e31802b5005.

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Chitnis, C. E., A. Chaudhuri, R. Horuk, A. O. Pogo, and L. H. Miller. "The domain on the Duffy blood group antigen for binding Plasmodium vivax and P. knowlesi malarial parasites to erythrocytes." Journal of Experimental Medicine 184, no. 4 (1996): 1531–36. http://dx.doi.org/10.1084/jem.184.4.1531.

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Plasmodium vivax and the related simian malarial parasite P. knowlesi use the Duffy blood group antigen as a receptor to invade human erythrocytes and region II of the parasite ligands for binding to this erythrocyte receptor. Here, we identify the peptide within the Duffy blood group antigen of human and rhesus erythrocytes to which the P. vivax and P. knowlesi ligands bind. Peptides from the NH2-terminal extracellular region of the Duffy antigen were tested for their ability to block the binding of erythrocytes to transfected Cos cells expressing on their surface region II of the Duffy-binding ligands. The binding site on the human Duffy antigen used by both the P. vivax and P. knowlesi ligands maps to a 35-amino acid region. A 34-amino acid peptide from the equivalent region of the rhesus Duffy antigen blocked the binding of P. vivax to human erythrocytes, although the P. vivax ligand expressed on Cos cells does not bind rhesus erythrocytes. The binding of the rhesus peptide, but not the rhesus erythrocyte, to the P. vivax ligand was explained by interference of carbohydrate with the binding process. Rhesus erythrocytes, treated with N-glycanase, bound specifically to P. vivax region II. Thus, the interaction of P. vivax ligand with human and rhesus erythrocytes appears to be mediated by a peptide-peptide interaction. Glycosylation of the rhesus Duffy antigen appears to block binding of the P. vivax ligand to rhesus erythrocytes.

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Hamad, Abdel Rahim A., Sean M. O'Herrin, Michael S. Lebowitz, et al. "Potent T Cell Activation with Dimeric Peptide–Major Histocompatibility Complex Class II Ligand: The Role of CD4 Coreceptor." Journal of Experimental Medicine 188, no. 9 (1998): 1633–40. http://dx.doi.org/10.1084/jem.188.9.1633.

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The interaction of the T cell receptor (TCR) with its cognate peptide–major histocompatibility complex (MHC) on the surface of antigen presenting cells (APCs) is a primary event during T cell activation. Here we used a dimeric IEk-MCC molecule to study its capacity to activate antigen-specific T cells and to directly analyze the role of CD4 in physically stabilizing the TCR–MHC interaction. Dimeric IEk-MCC stably binds to specific T cells. In addition, immobilized dimeric IEk-MCC can induce TCR downregulation and activate antigen-specific T cells more efficiently than anti-CD3. The potency of the dimeric IEk-MCC is significantly enhanced in the presence of CD4. However, CD4 does not play any significant role in stabilizing peptide-MHC–TCR interactions as it fails to enhance binding of IEk-MCC to specific T cells or influence peptide-MHC–TCR dissociation rate or TCR downregulation. Moreover, these results indicate that dimerization of peptide-MHC class II using an IgG molecular scaffold significantly increases its binding avidity leading to an enhancement of its stimulatory capacity while maintaining the physiological properties of cognate peptide–MHC complex. These peptide-MHC–IgG chimeras may, therefore, provide a novel approach to modulate antigen-specific T cell responses both in vitro and in vivo.

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Alvarez, Rene, M. Kariuki Njenga, Melissa Scott, and Bruce S. Seal. "Development of a Nucleoprotein-Based Enzyme-Linked Immunosorbent Assay Using a Synthetic Peptide Antigen for Detection of Avian Metapneumovirus Antibodies in Turkey Sera." Clinical Diagnostic Laboratory Immunology 11, no. 2 (2004): 245–49. http://dx.doi.org/10.1128/cdli.11.2.245-249.2004.

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ABSTRACT Avian metapneumoviruses (aMPV) cause an upper respiratory tract disease with low mortality but high morbidity, primarily in commercial turkeys, that can be exacerbated by secondary infections. There are three types of aMPV, of which type C is found only in the United States. The aMPV nucleoprotein (N) amino acid sequences of serotypes A, B, and C were aligned for comparative analysis. On the basis of the predicted antigenicity of consensus sequences, five aMPV-specific N peptides were synthesized for development of a peptide antigen enzyme-linked immunosorbent assay (aMPV N peptide-based ELISA) to detect aMPV-specific antibodies among turkeys. Sera from naturally and experimentally infected turkeys were used to demonstrate the presence of antibodies reactive to the chemically synthesized aMPV N peptides. Subsequently, aMPV N peptide 1, which had the sequence 10-DLSYKHAILKESQYTIKRDV-29, with variations at only three amino acids among aMPV serotypes, was evaluated as a universal aMPV ELISA antigen. Data obtained with the peptide-based ELISA correlated positively with total aMPV viral antigen-based ELISAs, and the peptide ELISA provided higher optical density readings. The results indicated that aMPV N peptide 1 can be used as a universal ELISA antigen to detect antibodies for all aMPV serotypes.

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Grube, Matthias, Stephanie Moritz, Ellen Obermann, et al. "Is Survivin a Possible Target Antigen for Cellular Immunotherapy in Multiple Myeloma?." Blood 106, no. 11 (2005): 5145. http://dx.doi.org/10.1182/blood.v106.11.5145.5145.

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Abstract Survivin is a member of the inhibitors of apoptosis family and is expressed in different types of malignancies including multiple myeloma. Cytotoxic T cells recognizing survivin epitopes can be elicited in vitro and by vaccination in human individuals. We performed this study to investigate whether survivin peptide specific CD8 T cells occur in patients with multiple myeloma (MM) and in healthy individuals. To detect antigen specific T-cells, we incubated PBMC from HLA-A2.1 positive patients and healthy individuals with antigen-presenting-cells (C1R-A2) pulsed or not pulsed with a recently described, HLA-A2.1 binding survivin derived peptide (Survpep). We used quantitative real time PCR to measure IFN-gamma mRNA expression for the detection of peptide specific CTL in 23 patients and 21 healthy individuals. A peptide stimulation index (SI, test peptide reactivity / no peptide reactivity) of 2.0 or greater was considered a positive response. CD8 T cells recognizing Survpep could be detected in vitro in 9/23 (39%) patients with MM (SI ranging from 2.9 to 83) and 1/21 (5%) healthy individuals (SI 7). Positive responses were confirmed by 4-colour flow cytometry for intracellular IFN-gamma production. T cells producing IFN-gamma were further analyzed for expression of CD45RA and CCR7 to determine phenotypic characteristics in two patients (SI 83 and 63) identifying them as terminally differentiated effector T cells (CD8+, CD45RA+, CCR7−). Additionally, positive expression of survivin antigen in tumor cells was confirmed by imminohistochemical analysis of patients bone marrow specimen. In conclusion we provide for the first time evidence for T cell reactivity against Survivin antigen in patients with MM. Our data suggest (1) the immunogenicity of survivin antigen in multiple myeloma and (2) that survivin may be a useful candidate antigen for cellular immunotherapy of multiple myeloma. CD8 T cell response (SI) to Survivin Peptide in patients with multiple myeloma (MM, n=23) and healthy individuals (HI, n=21) CD8 T cell response (SI) to Survivin Peptide in patients with multiple myeloma (MM, n=23) and healthy individuals (HI, n=21)

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Putterman, Chaim, and Betty Diamond. "Immunization with a Peptide Surrogate for Double-stranded DNA (dsDNA) Induces Autoantibody Production and Renal Immunoglobulin Deposition." Journal of Experimental Medicine 188, no. 1 (1998): 29–38. http://dx.doi.org/10.1084/jem.188.1.29.

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Anti–double-stranded DNA (dsDNA) antibodies are the serologic abnormality characteristically associated with systemic lupus erythematosus (SLE) and may play an important role in disease pathogenesis. Although the anti-dsDNA antibodies present in SLE are indicative of an antigen-driven response, the antigen has not been conclusively identified. By screening a phage peptide display library, we demonstrated previously that the decapeptide DWEYSVWLSN is specifically bound by the pathogenic murine IgG2b anti-dsDNA antibody R4A. To investigate the possibility that a protein antigen might trigger lupus-like autoimmunity, we immunized BALB/c mice with DWEYSVWLSN in adjuvant. Mice developed significant titers of IgG anti-dsDNA antibodies 2–3 wk after the initial immunization. Immunized mice also developed antibodies against some other lupus autoantigens, and immunoglobulin deposition was present in renal glomeruli at 49 d. Although an immune response to peptide and dsDNA was evident in BALB/c mice, there was little response in other inbred strains. This study demonstrates that lupus-like anti-dsDNA reactivity can be generated in nonautoimmune mice by immunization with a peptide antigen. Peptide-induced autoimmunity may prove useful in understanding the spreading of antigenic specificities targeted in SLE. However, most importantly, the demonstration that a peptide antigen can initiate a SLE-like immune response opens a new chapter on the potential antigenic stimuli that might trigger SLE.

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Hanyu, Yoshiro, Yuto Komeiji, and Mieko Kato. "Potentiating Antigen-Specific Antibody Production with Peptides Obtained from In Silico Screening for High-Affinity against MHC-II." Molecules 24, no. 16 (2019): 2949. http://dx.doi.org/10.3390/molecules24162949.

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Monoclonal antibodies with high affinity and specificity are essential for research and clinical purposes, yet remain difficult to produce. Agretope peptides that can potentiate antigen-specific antibody production have been reported recently. Here, we screened in silico for peptides with higher affinity against the agretope binding pocket in the MHC-II. The screening was based on the 3D crystal structure of a complex between MHC-II and a 14-mer peptide consisting of ovalbumin residues 323–339. Using this 14-mer peptide as template, we constructed a library of candidate peptides and screened for those that bound tightly to MHC-II. Peptide sequences that exhibited a higher binding affinity than the original ovalbumin peptide were identified. The peptide with the highest binding affinity was synthesized and its ability to boost antigen-specific antibody production in vivo and in vitro was assessed. In both cases, antigen-specific IgG antibody production was potentiated. Monoclonal antibodies were established by in vitro immunization using this peptide as immunostimulant, confirming the usefulness of such screened peptides for monoclonal antibody production.

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Doyle, Hester A., Jing Zhou, Martin J. Wolff, et al. "Isoaspartyl Post-translational Modification Triggers Anti-tumor T and B Lymphocyte Immunity." Journal of Biological Chemistry 281, no. 43 (2006): 32676–83. http://dx.doi.org/10.1074/jbc.m604847200.

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A hallmark of the immune system is the ability to ignore self-antigens. In attempts to bypass normal immune tolerance, a post-translational protein modification was introduced into self-antigens to break T and B cell tolerance. We demonstrate that immune tolerance is bypassed by immunization with a post-translationally modified melanoma antigen. In particular, the conversion of an aspartic acid to an isoaspartic acid within the melanoma antigen tyrosinase-related protein (TRP)-2 peptide-(181-188) makes the otherwise immunologically ignored TRP-2 antigen immunogenic. Tetramer analysis of iso-Asp TRP-2 peptide-immunized mice demonstrated that CD8+ T cells not only recognized the isoaspartyl TRP-2 peptide but also the native TRP-2 peptide. These CD8+ T cells functioned as cytotoxic T lymphocytes, as they effectively lysed TRP-2 peptide-pulsed targets both in vitro and in vivo. Potentially, post-translational protein modification can be utilized to trigger strong immune responses to either tumor proteins or potentially weakly immunogenic pathogens.

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Döring, Marius, Hanna Blees, Nicole Koller, et al. "Modulation of TAP-dependent antigen compartmentalization during human monocyte-to-DC differentiation." Blood Advances 3, no. 6 (2019): 839–50. http://dx.doi.org/10.1182/bloodadvances.2018027268.

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Abstract Dendritic cells (DCs) take up antigen in the periphery, migrate to secondary lymphoid organs, and present processed antigen fragments to adaptive immune cells and thus prime antigen-specific immunity. During local inflammation, recirculating monocytes are recruited from blood to the inflamed tissue, where they differentiate to macrophages and DCs. In this study, we found that monocytes showed high transporter associated with antigen processing (TAP)–dependent peptide compartmentalization and that after antigen pulsing, they were not able to efficiently stimulate antigen-specific T lymphocytes. Nevertheless, upon in vitro differentiation to monocyte-derived DCs, TAP-dependent peptide compartmentalization as well as surface major histocompatibility complex I turnover decreased and the cells efficiently restimulated T lymphocytes. Although TAP-dependent peptide compartmentalization decreased during DC differentiation, TAP expression levels increased. Furthermore, TAP relocated from early endosomes in monocytes to the endoplasmic reticulum (ER) and lysosomal compartments in DCs. Collectively, these data are compatible with the model that during monocyte-to-DC differentiation, the subcellular relocation of TAP and the regulation of its activity assure spatiotemporal separation of local antigen uptake and processing by monocytes and efficient T-lymphocyte stimulation by DCs.

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Celluzzi, C. M., J. I. Mayordomo, W. J. Storkus, M. T. Lotze, and L. D. Falo. "Peptide-pulsed dendritic cells induce antigen-specific CTL-mediated protective tumor immunity." Journal of Experimental Medicine 183, no. 1 (1996): 283–87. http://dx.doi.org/10.1084/jem.183.1.283.

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Cytotoxic T lymphocytes (CTLs) are a critical component of the immune response to tumors. Tumor-derived peptide antigens targeted by CTLs are being defined for several human tumors and are potential immunogens for the induction of specific antitumor immunity. Dendritic cells (DC) are potent antigen-presenting cells (APCs) capable of priming CTL responses in vivo. Here we show that major histocompatibility complex class I-presented peptide antigen pulsed onto dendritic APCs induces protective immunity to lethal challenge by a tumor transfected with the antigen gene. The immunity is antigen specific, requiring expression of the antigen gene by the tumor target, and is eliminated by in vivo depletion of CD8+ T cells. Furthermore, mice that have rejected the transfected tumor are protected from subsequent challenge with the untransfected parent tumor. These results suggest that immunization strategies using antigen-pulsed DC may be useful for inducing tumor-specific immune responses.

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Lu, Xiuju, James S. Gibbs, Heather D. Hickman, et al. "Endogenous viral antigen processing generates peptide-specific MHC class I cell-surface clusters." Proceedings of the National Academy of Sciences 109, no. 38 (2012): 15407–12. http://dx.doi.org/10.1073/pnas.1208696109.

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Sensitivity is essential in CD8+ T-cell killing of virus-infected cells and tumor cells. Although the affinity of the T-cell receptor (TCR) for antigen is relatively low, the avidity of T cell-antigen–presenting cell interactions is greatly enhanced by increasing the valence of the interaction. It is known that TCRs cluster into protein islands after engaging their cognate antigen (peptides bound to MHC molecules). Here, we show that mouse Kb class I molecules segregate into preformed, long-lasting (hours) clusters on the antigen-presenting cell surface based on their bound viral peptide. Peptide-specific Kb clustering occurs when source antigens are expressed by vaccinia or vesicular stomatitis virus, either as proteasome-liberated precursors or free intracellular peptides. By contrast, Kb–peptide complexes generated by incubating cells with synthetic peptides are extensively intermingled on the cell surface. Peptide-specific complex sorting is first detected in the Golgi complex, and compromised by removing the Kb cytoplasmic tail. Peptide-specific clustering is associated with increased T-cell sensitivity: on a per-complex basis, endogenous SIINFEKL activates T cells more efficiently than synthetic SIINFEKL, and wild-type Kb presents endogenous SIINFEKL more efficiently than tailless Kb. We propose that endogenous processing generates peptide-specific clusters of class I molecules to maximize the sensitivity and speed of T-cell immunosurveillance.

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Parks, Christopher A., Kalli R. Henning, Kevin D. Pavelko, et al. "Breaking tolerance with engineered class I antigen-presenting molecules." Proceedings of the National Academy of Sciences 116, no. 8 (2019): 3136–45. http://dx.doi.org/10.1073/pnas.1807465116.

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Successful efforts to activate T cells capable of recognizing weak cancer-associated self-antigens have employed altered peptide antigens to activate T cell responses capable of cross-reacting on native tumor-associated self. A limitation of this approach is the requirement for detailed knowledge about the altered self-peptide ligands used in these vaccines. In the current study we considered allorecognition as an approach for activating CTL capable of recognizing weak or self-antigens in the context of self-MHC. Nonself antigen-presenting molecules typically contain polymorphisms that influence interactions with the bound peptide and TCR interface. Recognition of these nonself structures results in peptide-dependent alloimmunity. Alloreactive T cells target their inducing alloantigens as well as third-party alloantigens but generally fail to target self-antigens. Certain residues located on the alpha-1/2 domains of class I antigen-presenting molecules primarily interface with TCR. These residues are more conserved within and across species than are residues that determine peptide antigen binding properties. Class I variants designed with amino acid substitutions at key positions within the conserved helical structures are shown to provide strong activating signals to alloreactive CD8 T cells while avoiding changes in naturally bound peptide ligands. Importantly, CTL activated in this manner can break self-tolerance by reacting to self-peptides presented by native MHC. The ability to activate self-tolerant T cells capable of cross-reacting on self-peptide-MHC in vivo represents an approach for inducing autoimmunity, with possible application in cancer vaccines.

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Yang, Amy X., Numju Chong, Yufei Jiang, Jennifer Catalano, Raj K. Puri, and Samir N. Khleif. "Molecular Characterization of Antigen-Peptide Pulsed Dendritic Cells: Immature Dendritic Cells Develop a Distinct Molecular Profile when Pulsed with Antigen Peptide." PLoS ONE 9, no. 1 (2014): e86306. http://dx.doi.org/10.1371/journal.pone.0086306.

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Jensen, P. E. "Regulation of antigen presentation by acidic pH." Journal of Experimental Medicine 171, no. 5 (1990): 1779–84. http://dx.doi.org/10.1084/jem.171.5.1779.

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The effect of pH on functional association of peptide antigens with APC membranes was investigated by using aldehyde-fixed B cells and class II-restricted T cell hybridomas to assess antigen/MHC complex formation. The results indicated that the rate and extent of functional peptide binding was markedly increased at pH 5.0 as compared with pH 7.3. The pH dependence of binding was preserved after pretreatment of fixed APC with pH 5.0 buffer, suggesting that pH had a direct effect on the interaction of peptide with the APC membrane. Similar results were obtained by using several peptides and I-Ad- and I-Ed-restricted T cells, indicating that pH may be of general importance in regulating the formation of functional antigen/class II MHC complexes.

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Ufret-Vincenty, Rafael L., Laura Quigley, Nancy Tresser, et al. "In Vivo Survival of Viral Antigen–specific T Cells that Induce Experimental Autoimmune Encephalomyelitis." Journal of Experimental Medicine 188, no. 9 (1998): 1725–38. http://dx.doi.org/10.1084/jem.188.9.1725.

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A peptide derived from the human papillomavirus L2 protein is recognized by a myelin basic protein (MBP)-specific T cell clone from a multiple sclerosis patient and by MBP-specific autoantibodies purified from multiple sclerosis brain tissue. We now show in mice that low doses of this papillomavirus peptide were optimal in selecting a subpopulation of papillomavirus peptide–specific T cells that cross-reacted with MBP(87–99) and with an unrelated viral peptide derived from the BSLF1 protein of Epstein-Barr virus (EBV). These low dose viral peptide– specific T cell lines were highly encephalitogenic. Splenocytes from mice transferred with viral peptide–specific T cells showed a vigorous response to both the papillomavirus and MBP peptides, indicating that viral antigen–specific T cells survived for a prolonged time in vivo. The EBV peptide, unable to prime and select an autoreactive T cell population, could still activate the low dose papillomavirus peptide–specific cells and induce central nervous system (CNS) autoimmunity. Cytokine profiles of papillomavirus peptide–specific encephalitogenic T cells and histopathology of CNS lesions resembled those induced by MBP. These results demonstrate conserved aspects in the recognition of the self-antigen and a cross-reactive viral peptide by human and murine MBP-specific T cell receptors. We demonstrate that a viral antigen, depending on its nature, dose, and number of exposures, may select autoantigen-specific T cells that survive in vivo and can trigger autoimmune disease after adoptive transfer.

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Mannie, Mark D., John P. Nardella, Gregory A. White, Paula Y. Arnold, and Daniel K. Davidian. "Class II MHC/Peptide Complexes on T Cell Antigen-Presenting Cells: Agonistic Antigen Recognition Inhibits Subsequent Antigen Presentation." Cellular Immunology 186, no. 2 (1998): 111–20. http://dx.doi.org/10.1006/cimm.1998.1301.

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van Ham, Marieke, Marcel van Lith, Björn Lillemeier, et al. "Modulation of the Major Histocompatibility Complex Class II–Associated Peptide Repertoire by Human Histocompatibility Leukocyte Antigen (Hla)-Do." Journal of Experimental Medicine 191, no. 7 (2000): 1127–36. http://dx.doi.org/10.1084/jem.191.7.1127.

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Antigen presentation by major histocompatibility complex class II molecules is essential for antibody production and T cell activation. For most class II alleles, peptide binding depends on the catalytic action of human histocompatibility leukocyte antigens (HLA)-DM. HLA-DO is selectively expressed in B cells and impedes the activity of DM, yet its physiological role remains unclear. Cell surface iodination assays and mass spectrometry of major histocompatibility complex class II–eluted peptides show that DO affects the antigenic peptide repertoire of class II. DO generates both quantitative and qualitative differences, and inhibits presentation of large-sized peptides. DO function was investigated under various pH conditions in in vitro peptide exchange assays and in antigen presentation assays using DO− and DO+ transfectant cell lines as antigen-presenting cells, in which effective acidification of the endocytic pathway was prevented with bafilomycin A1, an inhibitor of vacuolar ATPases. DO effectively inhibits antigen presentation of peptides that are loaded onto class II in endosomal compartments that are not very acidic. Thus, DO appears to be a unique, cell type–specific modulator mastering the class II–mediated immune response induced by B cells. DO may serve to increase the threshold for nonspecific B cell activation, restricting class II–peptide binding to late endosomal compartments, thereby affecting the peptide repertoire.

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Journal articles on the topic 'Peptide/antigen'

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