Littérature scientifique sur le sujet « Vaccine elicited antibodies »
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Articles de revues sur le sujet "Vaccine elicited antibodies"
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Willis, Elinor, Norbert Pardi, Kaela Parkhouse, Barbara L. Mui, Ying K. Tam, Drew Weissman et Scott E. Hensley. « Nucleoside-modified mRNA vaccination partially overcomes maternal antibody inhibition of de novo immune responses in mice ». Science Translational Medicine 12, no 525 (8 janvier 2020) : eaav5701. http://dx.doi.org/10.1126/scitranslmed.aav5701.
Texte intégralRésumé :
Maternal antibodies provide short-term protection to infants against many infections. However, they can inhibit de novo antibody responses in infants elicited by infections or vaccination, leading to increased long-term susceptibility to infectious diseases. Thus, there is a need to develop vaccines that are able to elicit protective immune responses in the presence of antigen-specific maternal antibodies. Here, we used a mouse model to demonstrate that influenza virus–specific maternal antibodies inhibited de novo antibody responses in mouse pups elicited by influenza virus infection or administration of conventional influenza vaccines. We found that a recently developed influenza vaccine, nucleoside-modified mRNA encapsulated in lipid nanoparticles (mRNA-LNP), partially overcame this inhibition by maternal antibodies. The mRNA-LNP influenza vaccine established long-lived germinal centers in the mouse pups and elicited stronger antibody responses than did a conventional influenza vaccine approved for use in humans. Vaccination with mRNA-LNP vaccines may offer a promising strategy for generating robust immune responses in infants in the presence of maternal antibodies.
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Gupta, Rajesh K., David N. Taylor, Dolores A. Bryla, John B. Robbins et Shousun C. Szu. « Phase 1 Evaluation of Vibrio choleraeO1, Serotype Inaba, Polysaccharide-Cholera Toxin Conjugates in Adult Volunteers ». Infection and Immunity 66, no 7 (1 juillet 1998) : 3095–99. http://dx.doi.org/10.1128/iai.66.7.3095-3099.1998.
Texte intégralRésumé :
ABSTRACT Conjugate vaccines were prepared by binding hydrazine-treated lipopolysaccharide (DeALPS) from Vibrio cholerae O1, serotype Inaba, to cholera toxin (CT) variants CT-1 and CT-2. Volunteers (n = 75) were injected with either 25 μg of DeALPS, alone or as a conjugate, or the licensed cellular vaccine containing 4 × 109 organisms each of serotypes Inaba and Ogawa per ml. No serious adverse reactions were observed. DeALPS alone did not elicit serum LPS or vibriocidal antibodies in mice and only low levels of immunoglobulin M (IgM) anti-LPS in the volunteers. Recipients of the cellular vaccine had the highest IgM anti-LPS levels, but the difference was not statistically significant from that elicited by the conjugates. The conjugates elicited the highest levels of IgG anti-LPS (DeALPS-CT-2 > DeALPS-CT-1 > cellular vaccine). Both conjugates and the cellular vaccine elicited vibriocidal antibodies: after 8 months, recipients of cellular vaccine had the highest geometric mean titer (1,249), followed by DeALPS-CT-2 (588) and DeALPS-CT-1 (330). The correlation coefficient between IgG anti-LPS and 2-mercaptoethanol (2-ME)-resistant vibriocidal antibodies was 0.81 (P = 0.0004). Convalescent sera from cholera patients had a mean vibriocidal titer of 2,525 that was removed by treatment with 2-ME. The vibriocidal activities of sera from all vaccine groups and from the patients were absorbed (>75%) by LPS but not by either CT-1 or CT-2. Conjugate-induced IgG vibriocidal antibodies persisted longer than those elicited by the whole-cell vaccine. Both conjugates, but not the cellular vaccine, elicited IgG anti-CT.
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Greaney, Allison J., Andrea N. Loes, Lauren E. Gentles, Katharine H. D. Crawford, Tyler N. Starr, Keara D. Malone, Helen Y. Chu et Jesse D. Bloom. « Antibodies elicited by mRNA-1273 vaccination bind more broadly to the receptor binding domain than do those from SARS-CoV-2 infection ». Science Translational Medicine 13, no 600 (8 juin 2021) : eabi9915. http://dx.doi.org/10.1126/scitranslmed.abi9915.
Texte intégralRésumé :
The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with mutations in key antibody epitopes has raised concerns that antigenic evolution could erode adaptive immunity elicited by prior infection or vaccination. The susceptibility of immunity to viral evolution is shaped in part by the breadth of epitopes targeted by antibodies elicited by vaccination or natural infection. To investigate how human antibody responses to vaccines are influenced by viral mutations, we used deep mutational scanning to compare the specificity of polyclonal antibodies elicited by either two doses of the mRNA-1273 COVID-19 vaccine or natural infection with SARS-CoV-2. The neutralizing activity of vaccine-elicited antibodies was more targeted to the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein compared to antibodies elicited by natural infection. However, within the RBD, binding of vaccine-elicited antibodies was more broadly distributed across epitopes compared to infection-elicited antibodies. This greater binding breadth means that single RBD mutations have less impact on neutralization by vaccine sera compared to convalescent sera. Therefore, antibody immunity acquired by natural infection or different modes of vaccination may have a differing susceptibility to erosion by SARS-CoV-2 evolution.
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Harris, Shannon L., Adam Finn et Dan M. Granoff. « Disparity in Functional Activity between Serum Anticapsular Antibodies Induced in Adults by Immunization with an Investigational Group A and C Neisseria meningitidis-Diphtheria Toxoid Conjugate Vaccine and by a Polysaccharide Vaccine ». Infection and Immunity 71, no 6 (juin 2003) : 3402–8. http://dx.doi.org/10.1128/iai.71.6.3402-3408.2003.
Texte intégralRésumé :
ABSTRACT Polysaccharide-protein conjugate vaccines elicit higher concentrations of serum anticapsular antibody in infants and children than do unconjugated polysaccharide vaccines. The conjugate-induced antibodies also have higher avidity and complement-mediated bactericidal activity. Similar vaccine-related differences in the magnitude or functional activity of antibody are observed infrequently in immunized adults. We compared the antibody responses of adults immunized with an investigational group A and C meningococcal conjugate vaccine to those elicited by an unconjugated meningococcal polysaccharide vaccine. Although there were no significant differences between the respective geometric mean bactericidal titers of the two vaccine groups, it took, on average, three- to fourfold higher concentrations of polysaccharide-induced serum anticapsular antibody to achieve 50% complement-mediated bacteriolysis than conjugate-induced antibody (P < 0.001 for groups A and C). At limiting doses, the polysaccharide-induced anticapsular antibodies also were less effective in conferring passive protection against meningococcal bacteremia in infant rats challenged with a group C strain (P < 0.04). The avidity index of the group C antibodies was higher in the conjugate vaccine group than in the polysaccharide vaccine group (P < 0.005). The disparities in the functional activity of the anticapsular antibodies elicited in adults by the two vaccines imply fundamental differences in the respective B-cell populations stimulated.
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Nuñez, Ivette A., Ying Huang et Ted M. Ross. « Next-Generation Computationally Designed Influenza Hemagglutinin Vaccines Protect against H5Nx Virus Infections ». Pathogens 10, no 11 (20 octobre 2021) : 1352. http://dx.doi.org/10.3390/pathogens10111352.
Texte intégralRésumé :
H5N1 COBRA hemagglutinin (HA) sequences, termed human COBRA-2 HA, were constructed through layering of HA sequences from viruses isolated from humans collected between 2004–2007 using only clade 2 strains. These COBRA HA proteins, when expressed on the surface of virus-like particles (VLP), elicited protective immune responses in mice, ferrets, and non-human primates. However, these vaccines were not as effective at inducing neutralizing antibodies against newly circulating viruses. Therefore, COBRA HA-based vaccines were updated in order to elicit protective antibodies against the current circulating clades of H5Nx viruses. Next-generation COBRA HA vaccines were designed to encompass the newly emerging viruses circulating in wild avian populations. HA amino acid sequences from avian and human H5 influenza viruses isolated between 2011–2017 were downloaded from the GISAID (Global Initiative on Sharing All Influenza Data). Mice were vaccinated with H5 COBRA rHA that elicited antibodies with hemagglutinin inhibition (HAI) activity against H5Nx viruses from five clades. The H5 COBRA rHA vaccine, termed IAN8, elicited protective immune responses against mice challenged with A/Sichuan/26621/2014 and A/Vietnam/1203/2004. This vaccine elicited antibodies with HAI activity against viruses from clades 2.2, 2.3.2.1, 2.3.4.2, 2.2.1 and 2.2.2. Lungs from vaccinated mice had decreased viral titers and the levels of cellular infiltration in mice vaccinated with IAN-8 rHA were similar to mice vaccinated with wild-type HA comparator vaccines or mock vaccinated controls. Overall, these next-generation H5 COBRA HA vaccines elicited protective antibodies against both historical H5Nx influenza viruses, as well as currently circulating clades of H5N1, H5N6, and H5N8 influenza viruses.
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Koeberling, Oliver, Isabel Delany et Dan M. Granoff. « A Critical Threshold of Meningococcal Factor H Binding Protein Expression Is Required for Increased Breadth of Protective Antibodies Elicited by Native Outer Membrane Vesicle Vaccines ». Clinical and Vaccine Immunology 18, no 5 (2 mars 2011) : 736–42. http://dx.doi.org/10.1128/cvi.00542-10.
Texte intégralRésumé :
ABSTRACTNative outer membrane vesicles (NOMV) (not detergent treated), which are prepared from recombinant strains with attenuated endotoxin activity and overexpressed factor H binding protein (fHbp), elicited broad serum bactericidal antibody responses in mice. The amount of overexpressed fHbp required for optimal immunogenicity is not known. In this study we prepared NOMV vaccines from LpxL1 knockout (ΔLpxL1) mutants with penta-acylated lipooligosaccharide and attenuated endotoxin activity. The recombinant strains had wild-type (1×) fHbp expression or were engineered for 3-fold- or 10-fold-increased fHbp expression (3× or 10× fHbp). Control vaccines included NOMV from ΔLpxL1/ΔfHbp mutants or recombinant fHbp. In mice, only the 10× fHbp NOMV vaccine elicited significantly higher serum IgG anti-fHbp antibody titers than the corresponding 1× fHbp NOMV or recombinant fHbp vaccine. The 10× fHbp NOMV vaccine also elicited higher bactericidal responses (P< 0.05) against five group B strains with heterologous PorA than the recombinant fHbp or 1× fHbp NOMV vaccine. The 3× fHbp NOMV vaccine gave higher bactericidal titers against only one strain. Serum bactericidal titers in mice immunized with the control ΔfHbp NOMV vaccines were <1:10, and bactericidal titers in mice immunized with the 10× fHbp NOMV vaccine were <1:10 after adsorption of anti-fHbp antibodies. Mixing antiserum to NOMV vaccines from fHbp knockout mutants with antiserum to recombinant fHbp did not increase anti-fHbp bactericidal titers. Thus, a critical threshold of increased fHbp expression is required for NOMV vaccines to elicit broad serum bactericidal responses, and the antibodies conferring protection are directed primarily at fHbp.
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Salat, Jiri, Petra Strakova et Daniel Ruzek. « Dynamics of Whole Virus and Non-Structural Protein 1 (NS1) IgG Response in Mice Immunized with Two Commercial Tick-Borne Encephalitis Vaccines ». Vaccines 10, no 7 (23 juin 2022) : 1001. http://dx.doi.org/10.3390/vaccines10071001.
Texte intégralRésumé :
The presence of a non-structural protein 1 (NS1) in tick-borne encephalitis (TBE) vaccines and the possible induction of an NS1-specific immune response in vaccinated individuals remains a somewhat controversial topic. Previously, we detected the presence of NS1 in the Encepur TBE vaccine by mass spectrometry and found the induction of NS1-specific IgG antibodies in mice vaccinated with the FSME-Immun TBE vaccine. Here, in this follow-up study, we examined the dynamics and extent of the NS1-specific IgG response in mice vaccinated with these two vaccines in more detail and compared it with the IgG response to the whole virus (WV). Mice were vaccinated at two-week intervals with a total of six doses of each vaccine, and levels of IgG antibodies to TBE virus WV and NS1 were measured by ELISA after each dose. Both vaccines elicited a robust anti-WV IgG response after two doses. The Encepur vaccine did not elicit NS1-specific IgG even after all six doses. In contrast, the FSME-Immun vaccine triggered the production of NS1-specific IgG after four doses. The results indicate that FSME-Immun is the only vaccine that elicits an NS1-specific antibody response in mice. However, compared to WV-specific IgG, the NS1-specific response is weaker, and a higher number of doses is required to induce detectable levels of NS1-specific IgG antibodies.
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Dapporto, Francesca, Serena Marchi, Margherita Leonardi, Pietro Piu, Piero Lovreglio, Nicola Decaro, Nicola Buonvino et al. « Antibody Avidity and Neutralizing Response against SARS-CoV-2 Omicron Variant after Infection or Vaccination ». Journal of Immunology Research 2022 (31 août 2022) : 1–9. http://dx.doi.org/10.1155/2022/4813199.
Texte intégralRésumé :
Background. The recently emerged SARS-CoV-2 Omicron variant exhibits several mutations on the spike protein, enabling it to escape the immunity elicited by natural infection or vaccines. Avidity is the strength of binding between an antibody and its specific epitope. The SARS-CoV-2 spike protein binds to its cellular receptor with high affinity and is the primary target of neutralizing antibodies. Therefore, protective antibodies should show high avidity. This study aimed at investigating the avidity of receptor-binding domain (RBD) binding antibodies and their neutralizing activity against the Omicron variant in SARS-CoV-2 infected patients and vaccinees. Methods. Samples were collected from 42 SARS-CoV-2 infected patients during the first pandemic wave, 50 subjects who received 2 doses of mRNA vaccine before the Omicron wave, 44 subjects who received 3 doses of mRNA vaccine, and 35 subjects who received heterologous vaccination (2 doses of adenovirus-based vaccine plus mRNA vaccine) during the Omicron wave. Samples were tested for the avidity of RBD-binding IgG and neutralizing antibodies against the wild-type SARS-CoV-2 virus and the Omicron variant. Results. In patients, RBD-binding IgG titers against the wild-type virus increased with time, but remained low. High neutralizing titers against the wild-type virus were not matched by high avidity or neutralizing activity against the Omicron variant. Vaccinees showed higher avidity than patients. Two vaccine doses elicited the production of neutralizing antibodies, but low avidity for the wild-type virus; antibody levels against the Omicron variant were even lower. Conversely, 3 doses of vaccine elicited high avidity and high neutralizing antibodies against both the wild-type virus and the Omicron variant. Conclusions. Repeated vaccination increases antibody avidity against the spike protein of the Omicron variant, suggesting that antibodies with high avidity and high neutralizing potential increase cross-protection against variants that carry several mutations on the RBD.
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Warner, Nikole L., et Kathryn M. Frietze. « Development of Bacteriophage Virus-Like Particle Vaccines Displaying Conserved Epitopes of Dengue Virus Non-Structural Protein 1 ». Vaccines 9, no 7 (2 juillet 2021) : 726. http://dx.doi.org/10.3390/vaccines9070726.
Texte intégralRésumé :
Dengue virus (DENV) is a major global health problem, with over half of the world’s population at risk of infection. Despite over 60 years of efforts, no licensed vaccine suitable for population-based immunization against DENV is available. Here, we describe efforts to engineer epitope-based vaccines against DENV non-structural protein 1 (NS1). NS1 is present in DENV-infected cells as well as secreted into the blood of infected individuals. NS1 causes disruption of endothelial cell barriers, resulting in plasma leakage and hemorrhage. Immunizing against NS1 could elicit antibodies that block NS1 function and also target NS1-infected cells for antibody-dependent cell cytotoxicity. We identified highly conserved regions of NS1 from all four DENV serotypes. We generated synthetic peptides to these regions and chemically conjugated them to bacteriophage Qβ virus-like particles (VLPs). Mice were immunized two times with the candidate vaccines and sera were tested for the presence of antibodies that bound to the cognate peptide, recombinant NS1 from all four DENV serotypes, and DENV-2-infected cells. We found that two of the candidate vaccines elicited antibodies that bound to recombinant NS1, and one candidate vaccine elicited antibodies that bound to DENV-infected cells. These results show that an epitope-specific vaccine against conserved regions of NS1 could be a promising approach for DENV vaccines or therapeutics to bind circulating NS1 protein.
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Giles, Brendan M., Stephanie J. Bissel, Dilhari R. DeAlmeida, Clayton A. Wiley et Ted M. Ross. « Antibody Breadth and Protective Efficacy Are Increased by Vaccination with Computationally Optimized Hemagglutinin but Not with Polyvalent Hemagglutinin-Based H5N1 Virus-Like Particle Vaccines ». Clinical and Vaccine Immunology 19, no 2 (21 décembre 2011) : 128–39. http://dx.doi.org/10.1128/cvi.05533-11.
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ABSTRACTOne of the challenges for developing an H5N1 influenza vaccine is the diversity of antigenically distinct isolates within this subtype. Previously, our group described a novel hemagglutinin (HA) derived from a methodology termed computationally optimized broadly reactive antigen (COBRA). This COBRA HA, when used as an immunogen, elicits a broad antibody response against H5N1 isolates from different clades. In this report, the immune responses elicited by the COBRA HA virus-like particle (VLP) vaccine were compared to responses elicited by a mixture of VLPs expressing representative HA molecules from clade 2.1, 2.2, and 2.3 primary H5N1 isolates (polyvalent). The COBRA HA VLP vaccine elicited higher-titer antibodies to a panel of H5N1 HA proteins than did the other VLPs. Both COBRA and polyvalent vaccines protected vaccinated mice and ferrets from experimental infection with highly lethal H5N1 influenza viruses, but COBRA-vaccinated animals had decreased viral replication, less inflammation in the lungs of mice, and reduced virus recovery in ferret nasal washes. Both vaccines had similar cellular responses postchallenge, indicating that higher-titer serum antibodies likely restrict the duration of viral replication. Furthermore, passively transferred immune serum from the COBRA HA VLP-vaccinated mice protected recipient animals more efficiently than immune serum from polyvalent-vaccinated mice. This is the first report comparing these two vaccine strategies. The single COBRA HA antigen elicited a broader antibody response and reduced morbidity and viral titers more effectively than a polyvalent mixture of primary H5N1 HA antigens.
Thèses sur le sujet "Vaccine elicited antibodies"
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NDONI, ENEA. « Characterization of the immune response and cross protection activity elicited by the Neisserial Heparin Binding Antigen (NHBA), a component of the 4CMenB vaccine ». Doctoral thesis, Università di Siena, 2017. http://hdl.handle.net/11365/1011542.
Texte intégralRésumé :
Invasive disease caused by capsular group B Neisseria meningitidis (MenB) is life threating disease causing hundred thousands of deaths every year, still remaining an unmet medical need in many countries. Although disease can be observed at all age groups, infants and adolescents are the most at risk populations showing the highest incidence in case numbers. Since the MenB capsule was not-immunogenic the development of a MenB vaccine which makes the use of other antigens becomes necessary. 4CMenB is a multicomponent vaccine against serogroup B N. meningitidis composed by three major protein antigens, factor H-binding protein (fHbp), Neisserial Heparin-Binding Antigen (NHBA) and Neisserial adhesin A (NadA), combined with outer membrane vesicles (OMVs) from the New-Zealand epidemic strain (NZ98/254). Neisserial Heparin Binding Antigen (NHBA) is a surface-exposed lipoprotein expressed by all N. meningitidis strains analyzed so far and is composed of two major domains, a highly variable amino-terminal (N-term) domain which anchors the protein on the bacterial outer membrane through the lipobox motif, and a highly conserved carboxyl-terminal (C-term) domain. These domains are separated by a short and quite conserved Arginine-rich (Arg-rich) motif which has been reported to be involved in different mechanisms that mediate meningococci adhesion, infection and survival within the host’s blood stream. NHBA is susceptible to cleavage by NalP, a bacterial protease which has its cleavage site upstream of the arginine region. Moreover human proteases such as human lactoferrin (hLf) and kallikrein are able to process NHBA downstream the the Arg-rich region. Both bacterial and human proteases-mediated cleavage releases the C-term of NHBA in the supernatant, while the N-term of the protein remains anchored on the bacterial surface. NalP cleavage did not impact SBA titers elicited by anti-NHBA antibodies but little is known about the impact that host’s proteases have on bactericidal titers. Based on sequence analysis it has been reported that NHBA has two major alleles, the so called “short” and “long” variants, which differentiate by the presence or absence of a 190 bp long fragment. Despite its sequence variability, NHBA is able to induce a robust and broad immune response against meningococcal strains expressing vaccine homologous and heterologous variants. Although anti-NHBA antibodies are able to induce bacterial killing when tested in serum bactericidal activity assay (SBA), the regions involved in eliciting cross protective immune response remain still unknown. Aims of this study were to use monoclonal antibodies (mAbs) raised against the NHBA vaccine variant peptide 2 (NHBAp2) to (i) map the NHBA regions involved in eliciting the functional response, (ii) test their ability to induce cross protection against strains expressing epidemiologically relevant homologous and heterologous NHBA variants, and (iii) investigate the molecular mechanism of NHBA-mediated bactericidal activity. To this end we used a panel of anti-NHBA mAbs selected to recognize different regions of the protein. Our results showed that only anti-N-term mAbs were able to induce killing of bacterial strains expressing the homologous NHBAp2 and closely related heterologous NHBA variants. Synergy between monoclonal antibodies targeting the N-term and the C-term of NHBA resulted in a significant increase of bactericidal titers but cross protection remained restricted to closely phylogenetic NHBA variants. Anti C-term mAbs were not able to induce SBA activity when tested individually, but surprisingly they became bactericidal when tested in combination. Moreover they were able to induce full cross protection against a panel of strains expressing phylogenetically distant heterologous NHBA variants.
Our results suggest that the partial release of the NHBA C-terminal portion upon NalP and serum proteases could explain why anti-C-term mAbs are not able to induce complement mediated bactericidal killing when tested individually. However, the simultaneous binding of C-term mapping mAbs on the same NHBA molecule can induce the formation of a very stable ternary complex that probably allows a more efficient C1q engagement and C3 deposition, thus leading to the observed co-operative bactericidal activity. These results suggest that synergy between anti-NHBA antibodies is at the basis of the mechanism of NHBA-induced bactericidal activity, which could explain the robust and cross-protective immune response elicited by anti-NHBA polyclonal antibodies following immunization. Collectively, the body of experimental data suggests that both domains of NHBA are required to elicit complement mediated bactericidal activity against strains expressing the vaccine homologous and heterologous NHBA variants.
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Chen, Yuxin. « Characterization of Envelope-Specific Antibody Response Elicited by HIV-1 Vaccines : A Dissertation ». eScholarship@UMMS, 2015. https://escholarship.umassmed.edu/gsbs_diss/760.
Texte intégralRésumé :
Despite 30 years of intensive research，an effective human immunodeficiency virus (HIV) vaccine still remains elusive. The desirable immune response capable of providing protection against HIV acquisition is still not clear. The accumulating evidence learned from a recent vaccine efficacy correlate study not only confirmed the importance of antibody responses, but also highlighted potential protective functions of antibodies with a broad repertoire of HIV-1 epitope specificities and a wide range of different antiviral mechanisms. This necessitates a deep understanding of the complexity and diversity of antibody responses elicited by HIV-1 vaccines. My dissertation characterizes antibody response profiles of HIV-1 Env antibodies elicited by several novel immunogens or different immunization regimens, in terms of magnitude, persistence, epitope specificity, binding affinity, and biological function.
First, to overcome the challenge of studying polyclonal sera without established assays, we expanded a novel platform to isolate Env-specific Rabbit mAbs (RmAb) elicited by DNA prime-protein boost immunization. These RmAbs revealed diverse epitope specificity and cross-reactivity against multiple gp120 antigens from more than one subtype, and several had potent and broad neutralizing activities against sensitive Tier 1 viruses. Further, structural analysis of two V3 mAbs demonstrated that a slight shift of the V3 epitope might have a dramatic impact on their neutralization activity. All of these observations provide a useful tool to study the induction of a desired type of antibody by different immunogens or different immunization regimens.
Since heavily glycosylated HIV Env protein is a critical component of an HIV vaccine, we wanted to determine the impact of the HIV Env-associated glycan shield on antibody responses. We were able to produce Env proteins with a selective and homogeneous pattern of N-glycosylation using a glycoengineered yeast cell line. Antigenicity of these novel Env proteins was examined by well-characterized human mAbs. Immunogenicity studies showed that they were immunogenic and elicited gp120- specific antibody responses. More significantly, sera elicited by glycan-modified gp120 protein immunogens revealed better neutralizing activities and increased diversity of epitopes compared to sera elicited by traditional gp120 produced in Chinese Hamster Ovary (CHO) cells.
Further, we examined the impact of the delivery order of DNA and protein immunization on antibody responses. We found that DNA prime-protein boost induced a comparable level of Env-specific binding Abs at the peak immunogenicity point to codelivery of DNA. However, antibody responses from DNA prime-protein boost had high avidity and diverse specificities, which improved potency and breadth of neutralizing Abs against Tier 1 viruses. Our data indicate that DNA vaccine priming of the immune system is essential for generation of high-quality antibodies.
Additionally, we determined the relative immunogenicity of gp120 and gp160 Env in the context of DNA prime-protein boost vaccination to induce high-quality antibody responses. Immunized sera from gp120 DNA primed animals, but not those primed with gp160 DNA, presented with distinct antibody repertoire specificities, a high magnitude of CD4 binding site-directed binding capabilities as well as neutralizing activities. We confirmed the importance of using the gp120 Env form at the DNA priming phase, which directly determined the quality of antibody response.
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Chen, Yuxin. « Characterization of Envelope-Specific Antibody Response Elicited by HIV-1 Vaccines : A Dissertation ». eScholarship@UMMS, 2001. http://escholarship.umassmed.edu/gsbs_diss/760.
Texte intégralRésumé :
Despite 30 years of intensive research，an effective human immunodeficiency virus (HIV) vaccine still remains elusive. The desirable immune response capable of providing protection against HIV acquisition is still not clear. The accumulating evidence learned from a recent vaccine efficacy correlate study not only confirmed the importance of antibody responses, but also highlighted potential protective functions of antibodies with a broad repertoire of HIV-1 epitope specificities and a wide range of different antiviral mechanisms. This necessitates a deep understanding of the complexity and diversity of antibody responses elicited by HIV-1 vaccines. My dissertation characterizes antibody response profiles of HIV-1 Env antibodies elicited by several novel immunogens or different immunization regimens, in terms of magnitude, persistence, epitope specificity, binding affinity, and biological function.
First, to overcome the challenge of studying polyclonal sera without established assays, we expanded a novel platform to isolate Env-specific Rabbit mAbs (RmAb) elicited by DNA prime-protein boost immunization. These RmAbs revealed diverse epitope specificity and cross-reactivity against multiple gp120 antigens from more than one subtype, and several had potent and broad neutralizing activities against sensitive Tier 1 viruses. Further, structural analysis of two V3 mAbs demonstrated that a slight shift of the V3 epitope might have a dramatic impact on their neutralization activity. All of these observations provide a useful tool to study the induction of a desired type of antibody by different immunogens or different immunization regimens.
Since heavily glycosylated HIV Env protein is a critical component of an HIV vaccine, we wanted to determine the impact of the HIV Env-associated glycan shield on antibody responses. We were able to produce Env proteins with a selective and homogeneous pattern of N-glycosylation using a glycoengineered yeast cell line. Antigenicity of these novel Env proteins was examined by well-characterized human mAbs. Immunogenicity studies showed that they were immunogenic and elicited gp120- specific antibody responses. More significantly, sera elicited by glycan-modified gp120 protein immunogens revealed better neutralizing activities and increased diversity of epitopes compared to sera elicited by traditional gp120 produced in Chinese Hamster Ovary (CHO) cells.
Further, we examined the impact of the delivery order of DNA and protein immunization on antibody responses. We found that DNA prime-protein boost induced a comparable level of Env-specific binding Abs at the peak immunogenicity point to codelivery of DNA. However, antibody responses from DNA prime-protein boost had high avidity and diverse specificities, which improved potency and breadth of neutralizing Abs against Tier 1 viruses. Our data indicate that DNA vaccine priming of the immune system is essential for generation of high-quality antibodies.
Additionally, we determined the relative immunogenicity of gp120 and gp160 Env in the context of DNA prime-protein boost vaccination to induce high-quality antibody responses. Immunized sera from gp120 DNA primed animals, but not those primed with gp160 DNA, presented with distinct antibody repertoire specificities, a high magnitude of CD4 binding site-directed binding capabilities as well as neutralizing activities. We confirmed the importance of using the gp120 Env form at the DNA priming phase, which directly determined the quality of antibody response.
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Vaine, Michael. « Antibody Responses Elicited by DNA Prime-Protein Boost HIV Vaccines : A Dissertation ». eScholarship@UMMS, 2010. https://escholarship.umassmed.edu/gsbs_diss/462.
Texte intégralRésumé :
The best known correlate of protection provided by vaccines is the presence of pathogen specific antibodies after immunization. However, against the Human Immunodeficiency Virus-1 (HIV-1) the mere presence of antibodies specific for the viral Envelope (Env) protein is not sufficient to provide protection. This necessitates in depth study of the humoral responses elicited during infection and by vaccination. While a significant amount of effort has been invested in studying the evolution of antibody responses to viral infection, only limited progress in understanding antibody responses elicited through vaccination has been made. In the studies described here, I attempt to rectify this deficiency by investigating how the quality of a humoral response is altered with the use of different immunization regimens, in particular a DNA prime-protein boost regimen, or with the use of different model HIV-1 Env gp120 immunogens. In a New Zealand White (NZW) rabbit model, we demonstrate that the broader neutralizing activity elicited with the DNA prime-protein boost regimen may be the result of the elicitation of a higher avidity antibody response and a unique profile of antibody specificities. Specifically, use of a DNA prime-protein boost regimen elicits antibodies targeted to the CD4 binding domain of the HIV-1 Env, a specificity that was not frequently observed when only protein based immunizations were administered.
We extended this analysis to sera from healthy human volunteers who participated in early phase HIV vaccine trials utilizing either a protein alone immunization regimen, a canarypox prime-protein boost immunization regimen, or a DNA prime-protein boost immunization regimen. Evaluation of sera from these trials demonstrated that the use of a DNA prime-protein boost regimen results in an antibody response with greater neutralization breadth characterized by an increased frequency and titer of antibodies targeted toward the CD4 binding site (CD4bs). In addition to this, the antibody response elicited by the DNA prime-protein boost regimen also exhibited the capability to mediate antibody dependent cell-mediated cytotoxicity (ADCC) activity as well as activation of the complement system.
Additionally, in an attempt to better understand the capabilities of antibodies elicited by a DNA prime-protein boost regimen, we generated gp120 specific monoclonal antibodies (mAbs) from a single DNA primed-protein boosted NZW rabbit. Analysis of mAbs produced from this animal revealed that use of this immunization regimen elicits an antibody repertoire with diverse epitope specificity and cross reactivity. Furthermore, these select mAbs are capable of neutralizing heterologous HIV isolates. Further application of mAb generation in rabbits may provide a valuable tool to study immunogenicity of different vaccines and immunization regimens.
Concurrently, while demonstrating that a DNA prime-protein boost regimen elicits a higher quality antibody response than that observed with other leading techniques, we also demonstrated that immunogen selection can play a vital role in the quality of the resulting antibody response. By immunizing with two closely related but phenotypically distinct model gp120 immunogens, known as B33 and LN40, we demonstrated that disparate gp120s have different intrinsic abilities to raise a heterologous neutralizing antibody response. Additionally, we showed that residues found within and flanking the b12 and CD4 binding sites play critical roles in modulating neutralizing activity of sera from animals immunized with LN40 gp120, indicating that the broader neutralizing activity seen with this immunogen may be due to differential elicitation of antibodies to this domain.
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Penn-Nicholson, Adam Garth. « Characterization and evaluation of approaches to elicit Broadly Reactive Neutralizing Antibodies against HIV-1 ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1205433621.
Texte intégralChapitres de livres sur le sujet "Vaccine elicited antibodies"
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Van Regenmortel, Marc H. V. « Immune Systems Rather than Antigenic Epitopes Elicit and Produce Protective Antibodies Against HIV ». Dans HIV/AIDS : Immunochemistry, Reductionism and Vaccine Design, 279–81. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-32459-9_22.
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Jong, Elaine C. « Immunizations ». Dans Schlossberg's Clinical Infectious Disease, sous la direction de Cheston B. Cunha, 761–80. Oxford University Press, 2021. http://dx.doi.org/10.1093/med/9780190888367.003.0113.
Texte intégralRésumé :
This chapter examines the long-lasting immunity against many serious infectious diseases that can be elicited through active immunization by the administration of specific antigens that stimulate the recipient host's production of protective antibodies. Protective levels of specific antibodies usually develop within 2 to 4 weeks after completion of the primary immunization regimen. The vaccine doses may be given orally, administered as mucosal vaccines, or given by injection using intradermal, subcutaneous, or intramuscular routes. The chapter also discusses passive immunization as the process by which protective immunity is obtained through transfer of preformed antibodies from an immune host to a nonimmune recipient, either as immunoglobulin or antibody-specific immunoglobulin. The chapter highlights host factors that influence protective efficacy resulting from active immunization. Vaccines used for recommended immunization coverage of children, adolescents, and adults are reviewed, along with relevant contraindications.
Actes de conférences sur le sujet "Vaccine elicited antibodies"
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Lohmueller, Jason J., Shuji Sato, Wan Cheung Cheung, Isabel Chu, Lana Popova, Christopher A. Manning, Katherine Crosby et al. « Abstract 2509 : Human anti-MUC1 antibodies elicited by a prophylactic cancer vaccine for mAb and CAR-modified T cell immunotherapies ». Dans Proceedings : AACR 106th Annual Meeting 2015 ; April 18-22, 2015 ; Philadelphia, PA. American Association for Cancer Research, 2015. http://dx.doi.org/10.1158/1538-7445.am2015-2509.
Texte intégralRapports d'organisations sur le sujet "Vaccine elicited antibodies"
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Knowles, Donald, et Monica Leszkowicz Mazuz. Transfected Babesia bovis expressing the anti-tick Bm86 antigen as a vaccine to limit tick infestation and protect against virulent challenge. United States Department of Agriculture, janvier 2014. http://dx.doi.org/10.32747/2014.7598160.bard.
Texte intégralRésumé :
Bovine babesiosis, caused by the apicomplexan parasites Babesiabovisand B. bigemina, is a major tick borne disease of cattle with significant economic importance globally. The vectors of Babesia parasites are R. (Boophilus) annulatusand R. microplus. In Israel these parasites are transmitted manly by R. annulatus. The main goal of the proposal was developing and testing a novel B. bovisvaccine based on stably transfected attenuated B. bovisexpressing the anti-tick Bm86 antigen. This required generating a transfected- attenuated B. bovisparasite containing a bidirectional promoter expressing both, the gfp- bsd selectable marker and the tick vaccine antigen Bm86. The vaccine was tested for its ability to elicit protective immune responses against T. annulatusticks. Efficient control of babesiosis is based on a complex scheme of integrated management, including preventive immunization, anti-babesial chemotherapy and control of tick populations. Live vaccines based on attenuated parasites are the most effective measure to control babesiosis, and are currently used in several countries, including Israel. Live attenuated parasites lead to a chronic infection and development of strong and long term immunity in vaccinated cattle. Still, live vaccines have several limitations, including the difficulty to distinguish among vaccinated and naturally infected cattle and potential for sporadic outbreaks in vaccinated animals. Tick limitation is essential to control babesiosis but the main measure to reduce tick infestation is traditionally approached using acaricides, which is limited by environmental concerns and the development of resistance by the ticks. Alternative tick-control measures including the use of anti-tick vaccines are emerging, and at least partial protective immunity has been achieved against tick vectors by vaccination with recombinant protective tick antigens (ie: Bm86). In addition, the Babesia vaccine development toolbox has been recently expanded with the development of transfection technology in Babesia parasites. In this approved proposal we successfully developed a Babesia live attenuated transfected vaccine, which is able to express a B. bovisMSA-1 signal-Bm86 chimera and eGFP genes under the control of the B. bovisef- 1 and actin promoters respectively. Genetic analysis demonstrated specific stable integration of the transfected genes in the expected ef-1 locus, and immunofluorescence analysis confirmed expression of Bm86 in the surface of transfected parasites. When applied to splenectomized calves, the transfected parasites were able to cause persistent B. bovisinfection with production of antibodies reactive with Bm86 for at least six months. In addition, partial protection against ticks was also observed upon challenging the vaccinated animals with R. annulatuslarvae. However, when used on intact calves, the vaccine failed to elicit detectable immune responses against Bm86, and we are still in the process of interpreting the data and make necessary changes in our experimental approaches. Overall, the results obtained here represent a step forward towards the development of integrated vaccines against both ticks and tick –borne pathogens, using the Babesia attenuated parasites as a platform to the delivery of exogenous protective antigens
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Splitter, Gary, et Menachem Banai. Microarray Analysis of Brucella melitensis Pathogenesis. United States Department of Agriculture, 2006. http://dx.doi.org/10.32747/2006.7709884.bard.
Texte intégralRésumé :
Original Objectives 1. To determine the Brucella genes that lead to chronic macrophage infection. 2. To identify Brucella genes that contribute to infection. 3. To confirm the importance of Brucella genes in macrophages and placental cells by mutational analysis. Background Brucella spp. is a Gram-negative facultative intracellular bacterium that infects ruminants causing abortion or birth of severely debilitated animals. Brucellosis continues in Israel, caused by B. melitensis despite an intensive eradication campaign. Problems with the Rev1 vaccine emphasize the need for a greater understanding of Brucella pathogenesis that could improve vaccine designs. Virulent Brucella has developed a successful strategy for survival in its host and transmission to other hosts. To invade the host, virulent Brucella establishes an intracellular niche within macrophages avoiding macrophage killing, ensuring its long-term survival. Then, to exit the host, Brucella uses placenta where it replicates to high numbers resulting in abortion. Also, Brucella traffics to the mammary gland where it is secreted in milk. Missing from our understanding of brucellosis is the surprisingly lillie basic information detailing the mechanisms that permit bacterial persistence in infected macrophages (chronic infection) and dissemination to other animals from infected placental cells and milk (acute infection). Microarray analysis is a powerful approach to determine global gene expression in bacteria. The close genomic similarities of Brucella species and our recent comparative genomic studies of Brucella species using our B. melitensis microarray, suqqests that the data obtained from studying B. melitensis 16M would enable understanding the pathogenicity of other Brucella organisms, particularly the diverse B. melitensis variants that confound Brucella eradication in Israel. Conclusions Results from our BARD studies have identified previously unknown mechanisms of Brucella melitensis pathogenesis- i.e., response to blue light, quorum sensing, second messenger signaling by cyclic di-GMP, the importance of genomic island 2 for lipopolysaccharide in the outer bacterial membrane, and the role of a TIR domain containing protein that mimics a host intracellular signaling molecule. Each one of these pathogenic mechanisms offers major steps in our understanding of Brucella pathogenesis. Strikingly, our molecular results have correlated well to the pathognomonic profile of the disease. We have shown that infected cattle do not elicit antibodies to the organisms at the onset of infection, in correlation to the stealth pathogenesis shown by a molecular approach. Moreover, our field studies have shown that Brucella exploit this time frame to transmit in nature by synchronizing their life cycle to the gestation cycle of their host succumbing to abortion in the last trimester of pregnancy that spreads massive numbers of organisms in the environment. Knowing the bacterial mechanisms that contribute to the virulence of Brucella in its host has initiated the agricultural opportunities for developing new vaccines and diagnostic assays as well as improving control and eradication campaigns based on herd management and linking diagnosis to the pregnancy status of the animals. Scientific and Agricultural Implications Our BARD funded studies have revealed important Brucella virulence mechanisms of pathogenesis. Our publication in Science has identified a highly novel concept where Brucella utilizes blue light to increase its virulence similar to some plant bacterial pathogens. Further, our studies have revealed bacterial second messengers that regulate virulence, quorum sensing mechanisms permitting bacteria to evaluate their environment, and a genomic island that controls synthesis of its lipopolysaccharide surface. Discussions are ongoing with a vaccine company for application of this genomic island knowledge in a Brucella vaccine by the U.S. lab. Also, our new technology of bioengineering bioluminescent Brucella has resulted in a spin-off application for diagnosis of Brucella infected animals by the Israeli lab by prioritizing bacterial diagnosis over serological diagnosis.