Journal articles: 'Protective antibodies'

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Vinson, Valda. "Protective neutralizing antibodies." Science 369, no. 6506 (August 20, 2020): 930.13–932. http://dx.doi.org/10.1126/science.369.6506.930-m.

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Cherry, James D., Erik L. Hewlett, and Edward A. Mortimer. "Protective antibodies in pertussis." Journal of Pediatrics 117, no. 2 (August 1990): 347. http://dx.doi.org/10.1016/s0022-3476(05)80580-3.

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Li, Hao, Xing-xing Wang, Bin Wang, Lei Fu, Guan Liu, Yu Lu, Min Cao, Hairong Huang, and Babak Javid. "Latently and uninfected healthcare workers exposed to TB make protective antibodies against Mycobacterium tuberculosis." Proceedings of the National Academy of Sciences 114, no. 19 (April 24, 2017): 5023–28. http://dx.doi.org/10.1073/pnas.1611776114.

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The role of Igs in natural protection against infection by Mycobacterium tuberculosis (Mtb), the causative agent of TB, is controversial. Although passive immunization with mAbs generated against mycobacterial antigens has shown protective efficacy in murine models of infection, studies in B cell-depleted animals only showed modest phenotypes. We do not know if humans make protective antibody responses. Here, we investigated whether healthcare workers in a Beijing TB hospital—who, although exposed to suprainfectious doses of pathogenic Mtb, remain healthy—make antibody responses that are effective in protecting against infection by Mtb. We tested antibodies isolated from 48 healthcare workers and compared these with 12 patients with active TB. We found that antibodies from 7 of 48 healthcare workers but none from active TB patients showed moderate protection against Mtb in an aerosol mouse challenge model. Intriguingly, three of seven healthcare workers who made protective antibody responses had no evidence of prior TB infection by IFN-γ release assay. There was also good correlation between protection observed in vivo and neutralization of Mtb in an in vitro human whole-blood assay. Antibodies mediating protection were directed against the surface of Mtb and depended on both immune complexes and CD4+ T cells for efficacy. Our results indicate that certain individuals make protective antibodies against Mtb and challenge paradigms about the nature of an effective immune response to TB.

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Flemming, Alexandra. "Viral vector delivers protective antibodies." Nature Reviews Drug Discovery 12, no. 8 (July 19, 2013): 580. http://dx.doi.org/10.1038/nrd4079.

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Gozdas, Hasan Tahsin, and Oguz Karabay. "Protective effect of tetanus antibodies." American Journal of Emergency Medicine 32, no. 9 (September 2014): 1128. http://dx.doi.org/10.1016/j.ajem.2014.05.009.

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Nussbaum, G., R. Yuan, A. Casadevall, and M. D. Scharff. "Immunoglobulin G3 blocking antibodies to the fungal pathogen Cryptococcus neoformans." Journal of Experimental Medicine 183, no. 4 (April 1, 1996): 1905–9. http://dx.doi.org/10.1084/jem.183.4.1905.

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Vaccination and infection can elicit protective and nonprotective antibodies to the fungus Cryptococcus neoformans in mice. The effect of nonprotective antibodies on host defense is unknown. In this study we used mixtures of protective and nonprotective monoclonal antibodies (mAbs) to determine if nonprotective mAbs blocked the activity of the protective mAbs. Antibody isotype and epitope specificity are important in determining the ability to prolong survival in mice given a lethal C. neoformans infection. Three different nonprotective immunoglobulin (Ig) G23 mAbs to cryptococcal capsular polysaccharide were used to study the interaction between the IgG3 isotype and protective IgG1 and IgG2a mAbs in murine cryptococcal infection. One IgG3 mAb reduced the protective efficacy of an IgG1 with identical epitope specificity. A second IgG3 mAb with different epitope specificity also reduced the protection provided by the IgG1 mAb. The protective efficacy of an IgG2a mAb was also dramatically decreased by still another IgG3 mAb. To our knowledge this is the first report of blocking antibodies to a fungal pathogen. The results have important implications for the development of vaccines and passive antibody therapy against C. neoformans.

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Danelli, Maria das Graças M., Lúcia M. Teixeira, Luiz Carlos D. Formiga, and J. Mauro Peralta. "Protective monoclonal antibodies to diphtheria toxin." Memórias do Instituto Oswaldo Cruz 86, no. 2 (June 1991): 265–67. http://dx.doi.org/10.1590/s0074-02761991000200017.

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Nosanchuk, J. "Protective Antibodies and Endemic Dimorphic Fungi." Current Molecular Medicine 5, no. 4 (June 1, 2005): 435–42. http://dx.doi.org/10.2174/1566524054022530.

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Hjelt, K., and P. C. Grauballe. "Protective Levels of Intestinal Rotavirus Antibodies." Journal of Infectious Diseases 161, no. 2 (February 1, 1990): 352–53. http://dx.doi.org/10.1093/infdis/161.2.352.

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Maamary, Jad, Taia T. Wang, Gene S. Tan, Peter Palese, and Jeffrey V. Ravetch. "Increasing the breadth and potency of response to the seasonal influenza virus vaccine by immune complex immunization." Proceedings of the National Academy of Sciences 114, no. 38 (September 5, 2017): 10172–77. http://dx.doi.org/10.1073/pnas.1707950114.

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The main barrier to reduction of morbidity caused by influenza is the absence of a vaccine that elicits broad protection against different virus strains. Studies in preclinical models of influenza virus infections have shown that antibodies alone are sufficient to provide broad protection against divergent virus strains in vivo. Here, we address the challenge of identifying an immunogen that can elicit potent, broadly protective, antiinfluenza antibodies by demonstrating that immune complexes composed of sialylated antihemagglutinin antibodies and seasonal inactivated flu vaccine (TIV) can elicit broadly protective antihemagglutinin antibodies. Further, we found that an Fc-modified, bispecific monoclonal antibody against conserved epitopes of the hemagglutinin can be combined with TIV to elicit broad protection, thus setting the stage for a universal influenza virus vaccine.

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Welsch, Jo Anne, and Dan Granoff. "Naturally Acquired Passive Protective Activity against Neisseria meningitidis Group C in the Absence of Serum Bactericidal Activity." Infection and Immunity 72, no. 10 (October 2004): 5903–9. http://dx.doi.org/10.1128/iai.72.10.5903-5909.2004.

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ABSTRACT The hallmark of immunity to meningococcal disease is a bactericidal titer in serum of ≥1:4 measured with human complement, but this threshold titer may underestimate the extent of protection. We used the infant rat model of meningococcal bacteremia to measure group C passive protective activity in serum samples from 91 unimmunized adults living in California. A total of 35 sera (38.5%) had passive protective activity. Sera with complement-mediated bactericidal titers of ≥1:4 were 3.4-fold more likely to confer protection (89%) than nonbactericidal sera (26%; P < 0.0001). Thus, bactericidal titers of ≥1:4 are a marker of protection, but this threshold lacks sensitivity for predicting protective activity. We investigated the 73 sera with bactericidal titers of <1:4 to determine the basis of protective activity. The 19 sera with protective activity had a higher geometric mean group C anticapsular antibody concentration (0.72 μg/ml) than the 54 sera that lacked protective activity (0.16 μg/ml; P < 0.001). Thus, protective activity in the absence of bactericidal activity was associated with higher concentrations of anticapsular antibodies, but not all sera with anticapsular antibodies conferred protection. Of 18 nonbactericidal sera with anticapsular antibody concentrations between 0.31 and 0.99 μg/ml, the 11 sera that conferred protection had a higher mean antibody avidity constant (21.9 nM−1) than the 7 nonprotective sera (14.6 nM−1; P < 0.03). Thus, in sera with titers of <1:4, protective activity is associated with higher-avidity group C anticapsular antibodies, which are present in concentrations insufficient to elicit complement-mediated bacteriolysis in vitro but sufficient to confer protection in an in vivo bacteremia model.

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Martin, Denis, Stéphane Rioux, Edith Gagnon, Martine Boyer, Josée Hamel, Nathalie Charland, and Bernard R. Brodeur. "Protection from Group B Streptococcal Infection in Neonatal Mice by Maternal Immunization with Recombinant Sip Protein." Infection and Immunity 70, no. 9 (September 2002): 4897–901. http://dx.doi.org/10.1128/iai.70.9.4897-4901.2002.

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ABSTRACT The protective potential of antibodies directed against group B streptococcus (GBS) Sip surface protein was determined by using the mouse neonatal infection model. Rabbit Sip-specific antibodies administered passively to pregnant mice protected their pups against a GBS lethal challenge. In addition, active immunization with purified recombinant Sip protein of female CD-1 mice induced the production of specific antibodies that also confer protection to the newborn pups against GBS strains of serotypes Ia/c, Ib, II, III, and V. These data confirm that Sip-specific antibodies can cross the placenta and conferred protective immunity against GBS infections.

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Xu, Meihui, Roland Züst, Ying Xiu Toh, Jennifer M. Pfaff, Kristen M. Kahle, Edgar Davidson, Benjamin J. Doranz, et al. "Protective Capacity of the Human Anamnestic Antibody Response during Acute Dengue Virus Infection." Journal of Virology 90, no. 24 (October 5, 2016): 11122–31. http://dx.doi.org/10.1128/jvi.01096-16.

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ABSTRACT Half of the world's population is exposed to the risk of dengue virus infection. Although a vaccine for dengue virus is now available in a few countries, its reported overall efficacy of about 60% is not ideal. Protective immune correlates following natural dengue virus infection remain undefined, which makes it difficult to predict the efficacy of new vaccines. In this study, we address the protective capacity of dengue virus-specific antibodies that are produced by plasmablasts a few days after natural secondary infection. Among a panel of 18 dengue virus-reactive human monoclonal antibodies, four groups of antibodies were identified based on their binding properties. While antibodies targeting the fusion loop of the glycoprotein of dengue virus dominated the antibody response, two smaller groups of antibodies bound to previously undescribed epitopes in domain II of the E protein. The latter, largely serotype-cross-reactive antibodies, demonstrated increased stability of binding at pH 5. These antibodies possessed weak to moderate neutralization capacity in vitro but were the most efficacious in promoting the survival of infected mice. Our data suggest that the cross-reactive anamnestic antibody response has a protective capacity despite moderate neutralization in vitro and a moderate decrease of viremia in vivo . IMPORTANCE Antibodies can protect from symptomatic dengue virus infection. However, it is not easy to assess which classes of antibodies provide protection because in vitro assays are not always predictive of in vivo protection. During a repeat infection, dengue virus-specific immune memory cells are reactivated and large amounts of antibodies are produced. By studying antibodies cloned from patients with heterologous secondary infection, we tested the protective value of the serotype-cross-reactive “recall” or “anamnestic” response. We found that results from in vitro neutralization assays did not always correlate with the ability of the antibodies to reduce viremia in a mouse model. In addition, a decrease of viremia in mice did not necessarily improve survival. The most protective antibodies were stable at pH 5, suggesting that antibody binding in the endosomes, after the antibody-virus complex is internalized, might be important to block virus spread in the organism.

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Curd, Rachel D., Berry Birdsall, Madhusudan Kadekoppala, Solabomi A. Ogun, Geoffrey Kelly, and Anthony A. Holder. "The structure of Plasmodium yoelii merozoite surface protein 1 19 , antibody specificity and implications for malaria vaccine design." Open Biology 4, no. 1 (January 2014): 130091. http://dx.doi.org/10.1098/rsob.130091.

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Merozoite surface protein 1 (MSP1) has been identified as a target antigen for protective immune responses against asexual blood stage malaria, but effective vaccines based on MSP1 have not been developed so far. We have modified the sequence of Plasmodium yoelii MSP1 19 (the C-terminal region of the molecule) and examined the ability of the variant proteins to bind protective monoclonal antibodies and to induce protection by immunization. In parallel, we examined the structure of the protein and the consequences of the amino acid changes. Naturally occurring sequence polymorphisms reduced the binding of individual protective antibodies, indicating that they contribute to immune evasion, but immunization with these variant proteins still provided protective immunity. One variant that resulted in the localized distortion of a loop close to the N-terminus of MSP1 19 almost completely ablated protection by immunization, indicating the importance of this region of MSP1 19 as a target for protective immunity and in vaccine development.

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Steiner, Donald J., Yoichi Furuya, and Dennis W. Metzger. "Detrimental Influence of Alveolar Macrophages on Protective Humoral Immunity duringFrancisella tularensisSchuS4 Pulmonary Infection." Infection and Immunity 86, no. 4 (January 8, 2018): e00787-17. http://dx.doi.org/10.1128/iai.00787-17.

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ABSTRACTOpsonizing antibody is a critical component of the host protective immune response against many respiratory pathogens. However, the role of antibodies in protection against pulmonary infection with highly virulentFrancisella tularensisstrain SchuS4 is unclear, and the mechanism that allowsF. tularensisto evade antibody-mediated bacterial clearance is not fully understood. We have now found that depletion of alveolar macrophages reveals an otherwise cryptic protective effect of opsonizing antibody. While antibody opsonization alone failed to confer any survival benefit against SchuS4 lung infection, significant protection was observed when mice were depleted of alveolar macrophages prior to infection. Blood immune signature analyses and bacterial burden measurements indicated that the treatment regimen blocked establishment of productive, systemic infection. In addition, protection was found to be dependent upon neutrophils. The results show for the first time a protective effect of opsonizing antibodies against highly virulentF. tularensisSchuS4 pulmonary infection through depletion of alveolar macrophages, the primary bacterial reservoir, and prevention of systemic dissemination. These findings have important implications for the potential use of therapeutic antibodies against intracellular pathogens that may escape clearance by residing within mucosal macrophages.

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Magliani, W., S. Conti, R. Frazzi, L. Ravanetti, D. Maffei, and L. Polonelli. "Protective Antifungal Yeast Killer Toxin-Like Antibodies." Current Molecular Medicine 5, no. 4 (June 1, 2005): 443–52. http://dx.doi.org/10.2174/1566524054022558.

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BERNARD, JACKY, B. REVEIL, I. NAJMAN, F. LIAUTAUD-ROGER, M. FOUCHARD, O. PICARD, A. CATTAN, et al. "Discrimination Between Protective and Enhancing HIV Antibodies." AIDS Research and Human Retroviruses 6, no. 2 (February 1990): 243–49. http://dx.doi.org/10.1089/aid.1990.6.243.

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Mukherjee, J., M. D. Scharff, and A. Casadevall. "Protective murine monoclonal antibodies to Cryptococcus neoformans." Infection and Immunity 60, no. 11 (1992): 4534–41. http://dx.doi.org/10.1128/iai.60.11.4534-4541.1992.

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Solomon, B. "Protective molecules in Alzheimer's disease: Therapeutic antibodies." Drug News & Perspectives 15, no. 7 (2002): 410. http://dx.doi.org/10.1358/dnp.2002.15.7.840076.

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Vollman, Kristan E., Nicole M. Acquisto, and Ryan P. Bodkin. "Response to “Protective effect of tetanus antibodies”." American Journal of Emergency Medicine 32, no. 9 (September 2014): 1128–29. http://dx.doi.org/10.1016/j.ajem.2014.05.049.

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Daniels, Calvin C., Kyung-Hyo Kim, Robert L. Burton, Shaper Mirza, Melissa Walker, Janice King, Yvette Hale, et al. "Modified Opsonization, Phagocytosis, and Killing Assays To Measure Potentially Protective Antibodies against Pneumococcal Surface Protein A." Clinical and Vaccine Immunology 20, no. 10 (August 7, 2013): 1549–58. http://dx.doi.org/10.1128/cvi.00371-13.

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ABSTRACTThe standard opsonophagocytosis killing assay (OPKA) for antibodies to pneumococcal capsular polysaccharide was modified to permit an evaluation of the protection-mediating antibodies to pneumococcal surface protein A (PspA). We found that by increasing the incubation time with the complement and phagocytes from 45 min to 75 min, the protective activity was readily detected. In another modification, we used a capsule type 2 target strain that expressed PspA but not pneumococcal surface protein C (PspC). With these modifications separately or in combination, rabbit antisera to the recombinant α-helical or proline-rich domains of PspA mediated >50% killing of the target strain. The ability of normal human sera to mediate the killing of pneumococci in this modified OPKA correlated with their levels of antibodies to PspA and their ability to protect mice against fatal infection with a type 3 strain. Passive protection of mice against pneumococci and killing in the modified OPKA were lost when normal human sera were adsorbed with recombinant PspA (rPspA) on Sepharose, thus supporting the potential utility of the modified OPKA to detect protective antibodies to PspA. In the standard OPKA, monoclonal antibodies to PspA were strongly protective in the presence of subprotective amounts of anti-capsule. Thus, the currently established high-throughput OPKA for antibodies to capsule could be modified in one of two ways to permit an evaluation of the opsonic efficacy of antibodies to PspA.

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Jin, Jing, and Graham Simmons. "Inhibitory Antibodies Targeting Emerging Viruses: Advancements and Mechanisms." Clinical and Vaccine Immunology 23, no. 7 (May 25, 2016): 535–39. http://dx.doi.org/10.1128/cvi.00136-16.

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From Ebola virus outbreaks in Western Africa to the introduction of chikungunya and Zika viruses in the Americas, new and neglected viruses continue to emerge and spread around the world. Due to a lack of existing vaccines or specific therapeutics, little other than supportive care and attempts to interrupt transmission can be provided during initial outbreaks. This has prompted a shift in vaccine design and development to identify novel epitopes and mechanisms of protection that may offer a broader range of protection against groups or whole families of viruses. Receptor-binding domains and other motifs within viral envelope proteins represent one excellent opportunity to target communal epitopes shared by related viruses. Similarly, for viruses where envelope participates in driving viral egress from infected cells, shared epitopes need to be identified to guide the development of broadly protective antibodies and vaccines. Here, we discuss recent advances in our understanding of broadly protective humoral responses for emerging viruses.

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Benhnia, Mohammed Rafii-El-Idrissi, Megan M. McCausland, John Laudenslager, Steven W. Granger, Sandra Rickert, Lilia Koriazova, Tomoyuki Tahara, Ralph T. Kubo, Shinichiro Kato, and Shane Crotty. "Heavily Isotype-Dependent Protective Activities of Human Antibodies against Vaccinia Virus Extracellular Virion Antigen B5." Journal of Virology 83, no. 23 (September 30, 2009): 12355–67. http://dx.doi.org/10.1128/jvi.01593-09.

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ABSTRACT Antibodies against the extracellular virion (EV or EEV) form of vaccinia virus are an important component of protective immunity in animal models and likely contribute to the protection of immunized humans against poxviruses. Using fully human monoclonal antibodies (MAbs), we now have shown that the protective attributes of the human anti-B5 antibody response to the smallpox vaccine (vaccinia virus) are heavily dependent on effector functions. By switching Fc domains of a single MAb, we have definitively shown that neutralization in vitro—and protection in vivo in a mouse model—by the human anti-B5 immunoglobulin G MAbs is isotype dependent, thereby demonstrating that efficient protection by these antibodies is not simply dependent on binding an appropriate vaccinia virion antigen with high affinity but in fact requires antibody effector function. The complement components C3 and C1q, but not C5, were required for neutralization. We also have demonstrated that human MAbs against B5 can potently direct complement-dependent cytotoxicity of vaccinia virus-infected cells. Each of these results was then extended to the polyclonal human antibody response to the smallpox vaccine. A model is proposed to explain the mechanism of EV neutralization. Altogether these findings enhance our understanding of the central protective activities of smallpox vaccine-elicited antibodies in immunized humans.

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Medina, Marcela, Julio Villena, Elisa Vintiñi, Elvira María Hebert, Raúl Raya, and Susana Alvarez. "Nasal Immunization with Lactococcus lactis Expressing the Pneumococcal Protective Protein A Induces Protective Immunity in Mice." Infection and Immunity 76, no. 6 (April 7, 2008): 2696–705. http://dx.doi.org/10.1128/iai.00119-08.

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ABSTRACT Nisin-controlled gene expression was used to develop a recombinant strain of Lactococcus lactis that is able to express the pneumococcal protective protein A (PppA) on its surface. Immunodetection assays confirmed that after the induction with nisin, the PppA antigen was predictably and efficiently displayed on the cell surface of the recombinant strain, which was termed L. lactis PppA. The production of mucosal and systemically specific antibodies in adult and young mice was evaluated after mice were nasally immunized with L. lactis PppA. Immunoglobulin M (IgM), IgG, and IgA anti-PppA antibodies were detected in the serum and bronchoalveolar lavage fluid of adult and young mice, which showed that PppA expressed in L. lactis was able to induce a strong mucosal and systemic immune response. Challenge survival experiments demonstrated that immunization with L. lactis PppA was able to increase resistance to systemic and respiratory infection with different pneumococcal serotypes, and passive immunization assays of naïve young mice demonstrated a direct correlation between anti-PppA antibodies and protection. The results presented in this study demonstrate three major characteristics of the effectiveness of nasal immunization with PppA expressed as a protein anchored to the cell wall of L. lactis: it elicited cross-protective immunity against different pneumococcal serotypes, it afforded protection against both systemic and respiratory challenges, and it induced protective immunity in mice of different ages.

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Zhao, Fan, Brian L. Cheng, Susan Boyle-Vavra, Maria-Luisa Alegre, Robert S. Daum, Anita S. Chong, and Christopher P. Montgomery. "Proteomic Identification ofsaeRS-Dependent Targets Critical for Protective Humoral Immunity against Staphylococcus aureus Skin Infection." Infection and Immunity 83, no. 9 (July 13, 2015): 3712–21. http://dx.doi.org/10.1128/iai.00667-15.

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RecurrentStaphylococcus aureusskin and soft tissue infections (SSTIs) are common despite detectable antibody responses, leading to the belief that the immune response elicited by these infections is not protective. We recently reported thatS. aureusUSA300 SSTI elicits antibodies that protect against recurrent SSTI in BALB/c but not C57BL/6 mice, and in this study, we aimed to uncover the specificity of the protective antibodies. Using a proteomic approach, we found thatS. aureusSSTI elicited broad polyclonal antibody responses in both BALB/c and C57BL/6 mice and identified 10S. aureusantigens against which antibody levels were significantly higher in immune BALB/c serum. Four of the 10 antigens identified are regulated by thesaeRSoperon, suggesting a dominant role forsaeRSin protection. Indeed, infection with USA300Δsaefailed to protect against secondary SSTI with USA300, despite eliciting a strong polyclonal antibody response against antigens whose expression is not regulated bysaeRS. Moreover, the antibody repertoire after infection with USA300Δsaelacked antibodies specific for 10saeRS-regulated antigens, suggesting that all or a subset of these antigens are necessary to elicit protective immunity. Infection with USA300Δhlaelicited modest protection against secondary SSTI, and complementation of USA300Δsaewithhlarestored protection but incompletely. Together, these findings support a role for both Hla and othersaeRS-regulated antigens in eliciting protection and suggest that host differences in immune responses tosaeRS-regulated antigens may determine whetherS. aureusinfection elicits protective or nonprotective immunity against recurrent infection.

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Kamei, Akinobu, Yamara S. Coutinho-Sledge, Joanna B. Goldberg, Gregory P. Priebe, and Gerald B. Pier. "Mucosal Vaccination with a Multivalent, Live-Attenuated Vaccine Induces Multifactorial Immunity againstPseudomonas aeruginosaAcute Lung Infection." Infection and Immunity 79, no. 3 (December 13, 2010): 1289–99. http://dx.doi.org/10.1128/iai.01139-10.

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ABSTRACTMany animal studies investigating adaptive immune effectors important for protection againstPseudomonas aeruginosahave implicated opsonic antibody to the antigenically variable lipopolysaccharide (LPS) O antigens as a primary effector. However, active and passive vaccination of humans against these antigens has not shown clinical efficacy. We hypothesized that optimal immunity would require inducing multiple immune effectors targeting multiple bacterial antigens. Therefore, we evaluated a multivalent live-attenuated mucosal vaccination strategy in a murine model of acuteP. aeruginosapneumonia to assess the contributions to protective efficacy of various bacterial antigens and host immune effectors. Vaccines combining 3 or 4 attenuated strains having different LPS serogroups were associated with the highest protective efficacy compared to vaccines with fewer components. Levels of opsonophagocytic antibodies, which were directed not only to the LPS O antigens but also to the LPS core and surface proteins, correlated with protective immunity. The multivalent live-attenuated vaccines overcame prior problems involving immunologic interference in the development of O-antigen-specific antibody responses when closely related O antigens were combined in multivalent vaccines. Antibodies to the LPS core were associated within vitrokilling andin vivoprotection against strains with O antigens not expressed by the vaccine strains, whereas antibodies to the LPS core and surface proteins augmented the contribution of O-antigen-specific antibodies elicited by vaccine strains containing a homologous O antigen. Local CD4 T cells in the lung also contributed to vaccine-based protection when opsonophagocytic antibodies to the challenge strain were absent. Thus, multivalent live-attenuated vaccines elicit multifactorial protective immunity toP. aeruginosalung infections.

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Riegler, Mann, Orihuela, and Tuomanen. "Opening the OPK Assay Gatekeeper: Harnessing Multi-Modal Protection by Pneumococcal Vaccines." Pathogens 8, no. 4 (October 23, 2019): 203. http://dx.doi.org/10.3390/pathogens8040203.

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Pneumococcal vaccine development is driven by the achievement of high activity in a single gatekeeper assay: the bacterial opsonophagocytic killing (OPK) assay. New evidence challenges the dogma that anti-capsular antibodies have only a single function that predicts success. The emerging concept of multi-modal protection presents an array of questions that are fundamental to adopting a new vaccine design process. If antibodies have hidden non-opsonic functions that are protective, should these be optimized for better vaccines? What would protein antigens add to protective activity? Are cellular immune functions additive to antibodies for success? Do different organs benefit from different modes of protection? Can vaccine activities beyond OPK protect the immunocompromised host? This commentary raises these issues at a time when capsule-only OPK assay-based vaccines are increasingly seen as a limiting strategy.

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Bournazos, Stylianos, David J. DiLillo, Arthur J. Goff, Pamela J. Glass, and Jeffrey V. Ravetch. "Differential requirements for FcγR engagement by protective antibodies against Ebola virus." Proceedings of the National Academy of Sciences 116, no. 40 (September 4, 2019): 20054–62. http://dx.doi.org/10.1073/pnas.1911842116.

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Ebola virus (EBOV) continues to pose significant threats to global public health, requiring ongoing development of multiple strategies for disease control. To date, numerous monoclonal antibodies (mAbs) that target the EBOV glycoprotein (GP) have demonstrated potent protective activity in animal disease models and are thus promising candidates for the control of EBOV. However, recent work in a variety of virus diseases has highlighted the importance of coupling Fab neutralization with Fc effector activity for effective antibody-mediated protection. To determine the contribution of Fc effector activity to the protective function of mAbs to EBOV GP, we selected anti-GP mAbs targeting representative, protective epitopes and characterized their Fc receptor (FcγR) dependence in vivo in FcγR humanized mouse challenge models of EBOV disease. In contrast to previous studies, we find that anti-GP mAbs exhibited differential requirements for FcγR engagement in mediating their protective activity independent of their distance from the viral membrane. Anti-GP mAbs targeting membrane proximal epitopes or the GP mucin domain do not rely on Fc–FcγR interactions to confer activity, whereas antibodies against the GP chalice bowl and the fusion loop require FcγR engagement for optimal in vivo antiviral activity. This complexity of antibody-mediated protection from EBOV disease highlights the structural constraints of FcγR binding for specific viral epitopes and has important implications for the development of mAb-based immunotherapeutics with optimal potency and efficacy.

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Mokaya, Jolynne, Derick Kimathi, Teresa Lambe, and George M. Warimwe. "What Constitutes Protective Immunity Following Yellow Fever Vaccination?" Vaccines 9, no. 6 (June 18, 2021): 671. http://dx.doi.org/10.3390/vaccines9060671.

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Yellow fever (YF) remains a threat to global health, with an increasing number of major outbreaks in the tropical areas of the world over the recent past. In light of this, the Eliminate Yellow Fever Epidemics Strategy was established with the aim of protecting one billion people at risk of YF through vaccination by the year 2026. The current YF vaccine gives excellent protection, but its use is limited by shortages in supply due to the difficulties in producing the vaccine. There are good grounds for believing that alternative fractional dosing regimens can produce strong protection and overcome the problem of supply shortages as less vaccine is required per person. However, immune responses to these vaccination approaches are yet to be fully understood. In addition, published data on immune responses following YF vaccination have mostly quantified neutralising antibody titers. However, vaccine-induced antibodies can confer immunity through other antibody effector functions beyond neutralisation, and an effective vaccine is also likely to induce strong and persistent memory T cell responses. This review highlights the gaps in knowledge in the characterisation of YF vaccine-induced protective immunity in the absence or presence of neutralising antibodies. The assessment of biophysical antibody characteristics and cell-mediated immunity following YF vaccination could help provide a comprehensive landscape of YF vaccine-induced immunity and a better understanding of correlates of protective immunity.

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Stadlbauer, Daniel, Xueyong Zhu, Meagan McMahon, Jackson S. Turner, Teddy J. Wohlbold, Aaron J. Schmitz, Shirin Strohmeier, et al. "Broadly protective human antibodies that target the active site of influenza virus neuraminidase." Science 366, no. 6464 (October 24, 2019): 499–504. http://dx.doi.org/10.1126/science.aay0678.

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Better vaccines against influenza virus are urgently needed to provide broader protection against diverse strains, subtypes, and types. Such efforts are assisted by the identification of novel broadly neutralizing epitopes targeted by protective antibodies. Influenza vaccine development has largely focused on the hemagglutinin, but the other major surface antigen, the neuraminidase, has reemerged as a potential target for universal vaccines. We describe three human monoclonal antibodies isolated from an H3N2-infected donor that bind with exceptional breadth to multiple different influenza A and B virus neuraminidases. These antibodies neutralize the virus, mediate effector functions, are broadly protective in vivo, and inhibit neuraminidase activity by directly binding to the active site. Structural and functional characterization of these antibodies will inform the development of neuraminidase-based universal vaccines against influenza virus.

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Yang, Xinghong, Theresa Thornburg, Kathryn Holderness, Zhiyong Suo, Ling Cao, Timothy Lim, Recep Avci, and David W. Pascual. "Serum Antibodies Protect against Intraperitoneal Challenge with EnterotoxigenicEscherichia coli." Journal of Biomedicine and Biotechnology 2011 (2011): 1–12. http://dx.doi.org/10.1155/2011/632396.

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To assess whether anticolonization factor antigen I (CFA/I) fimbriae antibodies (Abs) from enterotoxigenicEscherichia coli(ETEC) can protect against various routes of challenge, BALB/c mice were immunized with a live attenuatedSalmonellavaccine vector expressing CFA/I fimbriae. Vaccinated mice elicited elevated systemic IgG and mucosal IgA Abs, unlike mice immunized with the emptySalmonellavector. Mice were challenged with wild-type ETEC by the oral, intranasal (i.n.), and intraperitoneal (i.p.) routes. Naïve mice did not succumb to oral challenge, but did to i.n. challenge, as did immunized mice; however, vaccinated mice were protected against i.p. ETEC challenge. Two intramuscular (i.m.) immunizations with CFA/I fimbriae without adjuvant conferred 100% protection against i.p. ETEC challenge, while a single 30 μg dose conferred 88% protection. Bactericidal assays showed that ETEC is highly sensitive to anti-CFA/I sera. These results suggest that parenteral immunization with purified CFA/I fimbriae can induce protective Abs and may represent an alternative method to elicit protective Abs for passive immunity to ETEC.

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Wozniak, Karen L., Floyd L. Wormley, and Paul L. Fidel. "Candida-Specific Antibodies during Experimental Vaginal Candidiasis in Mice." Infection and Immunity 70, no. 10 (October 2002): 5790–99. http://dx.doi.org/10.1128/iai.70.10.5790-5799.2002.

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ABSTRACT Protective host defense mechanisms against vaginal Candida albicans infections are poorly understood. Although cell-mediated immunity (CMI) is the predominant host defense mechanism against most mucosal Candida infections, the role of CMI against vaginal candidiasis is uncertain, both in humans and in an experimental mouse model. The role of humoral immunity is equally unclear. While clinical observations suggest a minimal role for antibodies against vaginal candidiasis, an experimental rat model has provided evidence for a protective role for Candida-specific immunoglobulin A (IgA) antibodies. Additionally, Candida vaccination-induced IgM and IgG3 antibodies are protective in a mouse model of vaginitis. In the present study, the role of infection-induced humoral immunity in protection against experimental vaginal candidiasis was evaluated through the quantification of Candida-specific IgA, IgG, and IgM antibodies in serum and vaginal lavage fluids of mice with primary and secondary (partially protected) infection. In naïve mice, total, but not Candida-specific, antibodies were detected in serum and lavage fluids, consistent with lack of yeast colonization in mice. In infected mice, Candida-specific IgA and IgG antibodies were induced in serum with anamnestic responses to secondary infection. In lavage fluid, while Candida-specific antibodies were detectable, concentrations were extremely low with no anamnestic responses in mice with secondary infection. The incorporation of alternative protocols—including infections in a different strain of mice, prolongation of primary infection prior to secondary challenge, use of different enzyme-linked immunosorbent assay capture antigens, and concentration of lavage fluid—did not enhance local Candida-specific antibody production or detection. Additionally, antibodies were not removed from lavage fluids by being bound to Candida during infection. Together, these data suggest that antibodies are not readily present in vaginal secretions of infected mice and thus have a limited natural protective role against infection.

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Skvortsov, Alex, and Peter Gray. "A Simple Model for Assessment of Anti-Toxin Antibodies." BioMed Research International 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/230906.

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The toxins associated with infectious diseases are potential targets for inhibitors which have the potential for prophylactic or therapeutic use. Many antibodies have been generated for this purpose, and the objective of this study was to develop a simple mathematical model that may be used to evaluate the potential protective effect of antibodies. This model was used to evaluate the contributions of antibody affinity and concentration to reducing antibody-receptor complex formation and internalization. The model also enables prediction of the antibody kinetic constants and concentration required to provide a specified degree of protection. We hope that this model, once validated experimentally, will be a useful tool for in vitro selection of potentially protective antibodies for progression to in vivo evaluation.

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Seiler, Peter, Marie-Anne Bründler, Christine Zimmermann, Doris Weibel, Michael Bruns, Hans Hengartner, and Rolf M. Zinkernagel. "Induction of Protective Cytotoxic T Cell Responses in the Presence of High Titers of Virus-neutralizing Antibodies: Implications for Passive and Active Immunization." Journal of Experimental Medicine 187, no. 4 (February 16, 1998): 649–54. http://dx.doi.org/10.1084/jem.187.4.649.

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The effect of preexistent virus-neutralizing antibodies on the active induction of antiviral T cell responses was studied in two model infections in mice. Against the noncytopathic lymphocytic choriomeningitis virus (LCMV), pretreatment with neutralizing antibodies conferred immediate protection against systemic virus spread and controlled the virus below detectable levels. However, presence of protective antibody serum titers did not impair induction of antiviral cytotoxic T lymphocyte (CTL) responses after infection with 102 PFU of LCMV. These CTLs efficiently protected mice independent of antibodies against challenge with LCMV–glycoprotein recombinant vaccinia virus; they also protected against otherwise lethal lymphocytic choriomeningitis caused by intracerebral challenge with LCMV-WE, whereas transfused antibodies alone did not protect, and in some cases even enhanced, lethal lymphocytic choriomeningitis. Against the cytopathic vesicular stomatitis virus (VSV), specific CTLs and Th cells were induced in the presence of high titers of VSV-neutralizing antibodies after infection with 106 PFU of VSV, but not at lower virus doses. Taken together, preexistent protective antibody titers controlled infection but did not impair induction of protective T cell immunity. This is particularly relevant for noncytopathic virus infections since both virus-neutralizing antibodies and CTLs are essential for continuous virus control. Therefore, to vaccinate against such viruses parallel or sequential passive and active immunization may be a suitable vaccination strategy to combine advantages of both virus-neutralizing antibodies and CTLs.

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Stanisic, Danielle I., Freya J. I. Fowkes, Melanie Koinari, Sarah Javati, Enmoore Lin, Benson Kiniboro, Jack S. Richards, et al. "Acquisition of Antibodies against Plasmodium falciparum Merozoites and Malaria Immunity in Young Children and the Influence of Age, Force of Infection, and Magnitude of Response." Infection and Immunity 83, no. 2 (November 24, 2014): 646–60. http://dx.doi.org/10.1128/iai.02398-14.

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Individuals in areas ofPlasmodium falciparumendemicity develop immunity to malaria after repeated exposure. Knowledge of the acquisition and nature of protective immune responses toP. falciparumis presently limited, particularly for young children. We examined antibodies (IgM, IgG, and IgG subclasses) to merozoite antigens and their relationship to the prospective risk of malaria in children 1 to 4 years of age in a region of malaria endemicity in Papua New Guinea. IgG, IgG1, and IgG3 responses generally increased with age, were higher in children with active infection, and reflected geographic heterogeneity in malaria transmission. Antigenic properties, rather than host factors, appeared to be the main determinant of the type of IgG subclass produced. High antibody levels were not associated with protection from malaria; in contrast, they were typically associated with an increased risk of malaria. Adjustment for malaria exposure, using a novel molecular measure of the force of infection byP. falciparum, accounted for much of the increased risk, suggesting that the antibodies were markers of higher exposure toP. falciparum. Comparisons between antibodies in this cohort of young children and in a longitudinal cohort of older children suggested that the lack of protective association was explained by lower antibody levels among young children and that there is a threshold level of antibodies required for protection from malaria. Our results suggest that in populations with low immunity, such as young children, antibodies to merozoite antigens may act as biomarkers of malaria exposure and that, with increasing exposure and responses of higher magnitude, antibodies may act as biomarkers of protective immunity.

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Moffett, Howell F., Carson K. Harms, Kristin S. Fitzpatrick, Marti R. Tooley, Jim Boonyaratanakornkit, and Justin J. Taylor. "B cells engineered to express pathogen-specific antibodies protect against infection." Science Immunology 4, no. 35 (May 17, 2019): eaax0644. http://dx.doi.org/10.1126/sciimmunol.aax0644.

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Effective vaccines inducing lifelong protection against many important infections such as respiratory syncytial virus (RSV), HIV, influenza virus, and Epstein-Barr virus (EBV) are not yet available despite decades of research. As an alternative to a protective vaccine, we developed a genetic engineering strategy in which CRISPR-Cas9 was used to replace endogenously encoded antibodies with antibodies targeting RSV, HIV, influenza virus, or EBV in primary human B cells. The engineered antibodies were expressed efficiently in primary B cells under the control of endogenous regulatory elements, which maintained normal antibody expression and secretion. Using engineered mouse B cells, we demonstrated that a single transfer of B cells engineered to express an antibody against RSV resulted in potent and durable protection against RSV infection in RAG1-deficient mice. This approach offers the opportunity to achieve sterilizing immunity against pathogens for which traditional vaccination has failed to induce or maintain protective antibody responses.

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Nguyen, Melissa L., Sherry R. Crowe, Sridevi Kurella, Simon Teryzan, Brian Cao, Jimmy D. Ballard, Judith A. James, and A. Darise Farris. "Sequential B-Cell Epitopes of Bacillus anthracis Lethal Factor Bind Lethal Toxin-Neutralizing Antibodies." Infection and Immunity 77, no. 1 (November 3, 2008): 162–69. http://dx.doi.org/10.1128/iai.00788-08.

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ABSTRACT The bipartite anthrax lethal toxin (LeTx) consisting of protective antigen (PA) and lethal factor (LF) is a major virulence factor contributing to death from systemic Bacillus anthracis infection. The current vaccine elicits antibodies directed primarily to PA; however, in experimental settings serologic responses to LF can neutralize LeTx and contribute to protection against infection. The goals of the present study were to identify sequential B-cell epitopes of LF and to determine the capacity of these determinants to bind neutralizing antibodies. Sera of recombinant LF-immunized A/J mice exhibited high titers of immunoglobulin G anti-LF reactivity that neutralized LeTx in vitro 78 days after the final booster immunization and protected the mice from in vivo challenge with 3 50% lethal doses of LeTx. These sera bound multiple discontinuous epitopes, and there were major clusters of reactivity on native LF. Strikingly, all three neutralizing, LF-specific monoclonal antibodies tested bound specific peptide sequences that coincided with sequential epitopes identified in polyclonal antisera from recombinant LF-immunized mice. This study confirms that LF induces high-titer protective antibodies in vitro and in vivo. Moreover, the binding of short LF peptides by LF-specific neutralizing monoclonal antibodies suggests that generation of protective antibodies by peptide vaccination may be feasible for this antigen. This study paves the way for a more effective anthrax vaccine by identifying discontinuous peptide epitopes of LF.

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Beeson, James G., Stephen J. Rogerson, Salenna R. Elliott, and Michael F. Duffy. "Targets of Protective Antibodies to Malaria during Pregnancy." Journal of Infectious Diseases 192, no. 9 (November 2005): 1647–50. http://dx.doi.org/10.1086/496895.

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Lopez, O. J., and F. A. Osorio. "Role of neutralizing antibodies in PRRSV protective immunity." Veterinary Immunology and Immunopathology 102, no. 3 (December 2004): 155–63. http://dx.doi.org/10.1016/j.vetimm.2004.09.005.

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BICKLE, Q. D., B. J. ANDREWS, and M. G. TAYLOR. "Schistosoma mansoni: characterization of two protective monoclonal antibodies." Parasite Immunology 8, no. 1 (January 1986): 95–107. http://dx.doi.org/10.1111/j.1365-3024.1986.tb00836.x.

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FOMSGAARD, ANDERS. "Antibodies to lipopolysaccharides: Some diagnostic and protective aspects." APMIS 98, S18 (October 1990): 5–38. http://dx.doi.org/10.1111/j.1600-0463.1990.tb05699.x.

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Skurnik, David, Damien Roux, Stephanie Pons, Thomas Guillard, Xi Lu, Colette Cywes-Bentley, and Gerald B. Pier. "Extended-spectrum antibodies protective against carbapenemase-producing Enterobacteriaceae." Journal of Antimicrobial Chemotherapy 71, no. 4 (January 7, 2016): 927–35. http://dx.doi.org/10.1093/jac/dkv448.

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Nielsen, Susanne Vinther, Uffe B. Skov Sørensen, and Jørgen Henrichsen. "Antibodies against pneumococcal C-polysaccharide are not protective." Microbial Pathogenesis 14, no. 4 (April 1993): 299–305. http://dx.doi.org/10.1006/mpat.1993.1029.

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Oon, Lynette L. E., Alistair King, Julie A. Higgins, Christine A. Lee, Peter B. A. Kernoff, and Alison H. Goodall. "Protective antibodies to hepatitis B virus in haemophiliacs." Journal of Medical Virology 33, no. 1 (January 1991): 19–25. http://dx.doi.org/10.1002/jmv.1890330105.

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Ulmansky, Rina, and Yaakov Naparstek. "Protective antibodies against HSP60 for autoimmune inflammatory diseases." Clinical Immunology 186 (January 2018): 63. http://dx.doi.org/10.1016/j.clim.2017.07.016.

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Kuraoka, Masayuki, Yu Adachi, and Yoshimasa Takahashi. "Hide and seek: interplay between influenza viruses and B cells." International Immunology 32, no. 9 (April 18, 2020): 605–11. http://dx.doi.org/10.1093/intimm/dxaa028.

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Abstract Influenza virus constantly acquires genetic mutations/reassortment in the major surface protein, hemagglutinin (HA), resulting in the generation of strains with antigenic variations. There are, however, HA epitopes that are conserved across influenza viruses and are targeted by broadly protective antibodies. A goal for the next-generation influenza vaccines is to stimulate B-cell responses against such conserved epitopes in order to provide broad protection against divergent influenza viruses. Broadly protective B cells, however, are not easily activated by HA antigens with native structure, because the virus has multiple strategies to escape from the humoral immune responses directed to the conserved epitopes. One such strategy is to hide the conserved epitopes from the B-cell surveillance by steric hindrance. Technical advancement in the analysis of the human B-cell antigen receptor (BCR) repertoire has dissected the BCRs to HA epitopes that are hidden in the native structure but are targeted by broadly protective antibodies. We describe here the characterization and function of broadly protective antibodies and strategies that enable B cells to seek these hidden epitopes, with potential implications for the development of universal influenza vaccines.

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TAMURA, Y., M. KIJIMA, K. OHISHI, T. TAKAHASHI, S. SUZUKI, and M. NAKAMURA. "Antigenic analysis of Clostridium chauvoei flagella with protective and non-protective monoclonal antibodies." Journal of General Microbiology 138, no. 3 (March 1, 1992): 537–42. http://dx.doi.org/10.1099/00221287-138-3-537.

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Thomas, John M., Scott T. Moen, Bryan T. Gnade, Diego A. Vargas-Inchaustegui, Sheri M. Foltz, Giovanni Suarez, Hans W. Heidner, Rolf König, Ashok K. Chopra, and Johnny W. Peterson. "Recombinant Sindbis Virus Vectors Designed To Express Protective Antigen of Bacillus anthracis Protect Animals from Anthrax and Display Synergy with Ciprofloxacin." Clinical and Vaccine Immunology 16, no. 11 (September 16, 2009): 1696–99. http://dx.doi.org/10.1128/cvi.00173-09.

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ABSTRACT Recombinant Sindbis viruses were engineered to express alternative forms of the protective antigen (PA) of Bacillus anthracis. The recombinant viruses induced PA-specific immunoglobulin G and neutralizing antibodies in Swiss Webster mice. Vaccination with the recombinant viruses induced immunity that offered some protection from a lethal Ames strain spore challenge and synergized the protective effects of ciprofloxacin.

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Smith, S. Abigail, and Cynthia A. Derdeyn. "Harnessing the protective potential of HIV-1 neutralizing antibodies." F1000Research 5 (January 5, 2016): 20. http://dx.doi.org/10.12688/f1000research.7254.1.

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Recent biological, structural, and technical advances are converging within the HIV-1 vaccine field to harness the power of antibodies for prevention and therapy. Numerous monoclonal antibodies with broad neutralizing activity against diverse HIV-1 isolates have now been identified, revealing at least five sites of vulnerability on the envelope (Env) glycoproteins. While there are practical and technological barriers blocking a clear path from broadly neutralizing antibodies (bNAb) to a protective vaccine, this is not a dead end. Scientists are revisiting old approaches with new technology, cutting new trails through unexplored territory, and paving new roads in the hopes of preventing HIV-1 infection. Other promising avenues to capitalize on the power of bNAbs are also being pursued, such as passive antibody immunotherapy and gene therapy approaches. Moreover, non-neutralizing antibodies have inhibitory activities that could have protective potential, alone or in combination with bNAbs. With a new generation of bNAbs, and a clinical trial that associated antibodies with reduced acquisition, the field is closer than ever to developing strategies to use antibodies against HIV-1.

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Oeuvray, C., H. Bouharoun-Tayoun, H. Gras-Masse, E. Bottius, T. Kaidoh, M. Aikawa, MC Filgueira, A. Tartar, and P. Druilhe. "Merozoite surface protein-3: a malaria protein inducing antibodies that promote Plasmodium falciparum killing by cooperation with blood monocytes." Blood 84, no. 5 (September 1, 1994): 1594–602. http://dx.doi.org/10.1182/blood.v84.5.1594.1594.

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Abstract We have previously found that the acquired protection against malaria implicates a mechanism of defense that relies on the cooperation between cytophilic antibodies and monocytes. Accordingly, an assay of antibody-dependent cellular inhibition (ADCI) of parasite growth was used as a means of selecting for molecules capable of inducing protective immunity to malaria. This allowed us to identify in the sera of clinically protected subjects an antibody specificity that promotes parasite killing mediated by monocytes. This antibody is directed to a novel merozoite surface protein (MSP-3) of a molecular mass of 48 kD. Purified IgG from protected subjects are effective in ADCI and those directed against MSP-3 are predominantly cytophilic. In contrast, in nonprotected individuals, whose antibodies are not effective in ADCI, anti-MSP-3 antibodies are mostly noncytophilic. A region in MSP-3 targetted by antibodies effective in the ADCI assay was identified and its sequence was determined; it contains an epitope not defined by a repetitive structure and does not appear to be polymorphic. Antibodies raised in mice against a peptide containing this epitope, as well as human antibodies immunopurified on this peptide, elicit a strong inhibition of Plasmodium falciparum growth in ADCI assay, whereas control antibodies, directed to peptides from other molecules, do not. The correlation between isotypes of antibodies produced against the 48- kD epitopes, clinical protection, and the ability of specific anti-MSP- 3 antibodies to block the parasite schizogony in the ADCI assay suggests that this molecule is involved in eliciting protective mechanisms.

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Journal articles on the topic 'Protective antibodies'

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