There is still no safe and effective vaccine against dengue virus infection. Epidemics of dengue virus infection are increasingly a threat to human health around the world. Antibodies generated in ...response to dengue infection have been shown to impact disease development and effectiveness of dengue vaccine. In this study, we investigated monoclonal antibody responses to an experimental dengue vaccine in rhesus macaques. Variable regions of both heavy chain (VH) and light chain (VL) were cloned from single antibody-secreting B cells. A total of 780 monoclonal antibodies (mAbs) composed of paired VH and VL were characterized. Results show that the vaccination induces mAbs with diverse germline sequences and a wide range of binding affinities. Six potent neutralizing mAbs were identified among 130 dengue envelope protein binders. Critical amino acids for each neutralizing antibody binding to the dengue envelope protein were identified by alanine scanning of mutant libraries. Diverse epitopes were identified, including epitopes on the lateral ridge of DIII, the I-III hinge, the bc loop adjacent to the fusion loop of DII, and the β-strands and loops of DI. Significantly, one of the neutralizing mAbs has a previously unknown epitope in DII at the interface of the envelope and membrane protein and is capable of neutralizing all four dengue serotypes. Taken together, the results of this study not only provide preclinical validation for the tested experimental vaccine, but also shed light on a potential application of the rhesus macaque model for better dengue vaccine evaluation and design of vaccines and immunization strategies.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Respiratory syncytial virus (RSV) infection is the leading cause of hospitalization and infant mortality under six months of age worldwide; therefore, the prevention of RSV infection in all infants ...represents a significant unmet medical need. Here we report the isolation of a potent and broadly neutralizing RSV monoclonal antibody derived from a human memory B-cell. This antibody, RB1, is equipotent on RSV A and B subtypes, potently neutralizes a diverse panel of clinical isolates in vitro and demonstrates in vivo protection. It binds to a highly conserved epitope in antigenic site IV of the RSV fusion glycoprotein. RB1 is the parental antibody to MK-1654 which is currently in clinical development for the prevention of RSV infection in infants.
Herpes zoster (shingles) causes significant morbidity in immune compromised hosts and older adults. Whereas a vaccine is available for prevention of shingles, its efficacy declines with age. To help ...to understand the mechanisms driving vaccinal responses, we constructed a multiscale, multifactorial response network (MMRN) of immunity in healthy young and older adults immunized with the live attenuated shingles vaccine Zostavax. Vaccination induces robust antigen-specific antibody, plasmablasts, and CD4+ T cells yet limited CD8+ T cell and antiviral responses. The MMRN reveals striking associations between orthogonal datasets, such as transcriptomic and metabolomics signatures, cell populations, and cytokine levels, and identifies immune and metabolic correlates of vaccine immunity. Networks associated with inositol phosphate, glycerophospholipids, and sterol metabolism are tightly coupled with immunity. Critically, the sterol regulatory binding protein 1 and its targets are key integrators of antibody and T follicular cell responses. Our approach is broadly applicable to study human immunity and can help to identify predictors of efficacy as well as mechanisms controlling immunity to vaccination.
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•Integrative analysis of orthogonal data on response to vaccination•Strong association between plasma metabolomics and PBMC transcriptomics•Sterol metabolism integrates cellular and humoral responses•Metabolic phenotype, such as inositol phosphate metabolism, influences immune outcome
An integrated metabolic response underlies the immune response to shingles vaccine in humans.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Respiratory syncytial virus (RSV) is a leading cause of serious lower respiratory tract disease in young children and older adults throughout the world. Prevention of severe RSV disease through ...active immunization is optimal but no RSV vaccine has been licensed so far. Immune mechanisms of protection against RSV infection in humans have not been fully established, thus a comprehensive characterization of virus-specific immune responses in a relevant animal model will be beneficial in defining correlates of protection. In this study, we infected juvenile naive AGMs with RSV A2 strain and longitudinally assessed virus-specific humoral and cellular immune responses in both peripheral blood and the respiratory tract. RSV viral loads at nasopharyngeal surfaces and in the lung peaked at around day 5 following infection, and then largely resolved by day 10. Low levels of neutralizing antibody titers were detected in serum, with similar kinetics as RSV fusion (F) protein-binding IgG antibodies. RSV infection induced CD8+, but very little CD4+, T lymphocyte responses in peripheral blood. Virus-specific CD8+ T cell frequencies were ~10 fold higher in bronchoaveolar lavage (BAL) compared to peripheral blood and exhibited effector memory (CD95+CD28-) / tissue resident memory (CD69+CD103+) T (TRM) cell phenotypes. The kinetics of virus-specific CD8+ T cells emerging in peripheral blood and BAL correlated with declining viral titers, suggesting that virus-specific cellular responses contribute to the clearance of RSV infection. RSV-experienced AGMs were protected from subsequent exposure to RSV infection. Additional studies are underway to understand protective correlates in these seropositive monkeys.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Zostavax is a safe vaccine to prevent shingles/postherpetic neuralgia.•Zostavax is a weak stimulator of innate immune responses.•Zostavax changes several metabolomic pathways which are correlated ...with immune outcome.•Zostavax elicits polyfunctional VZV-specific CD4+ T cells and low CD8+ T cell responses.•Zostavax boosts antibody responses which are strongly influenced by pre-existing antibody levels.
Zostavax is a live-attenuated varicella zoster virus (VZV) vaccine recommended for use in adults >50 years of age to prevent shingles. The main risk factor for the development of shingles is age, which correlates with decreasing cell-mediated immunity. These data suggest a predominant role of T cell immunity in controlling VZV latency. However, other components of the immune system may also contribute. In this review, we will discuss how the immune system responds to Zostavax, focusing on recent studies examining innate immunity, transcriptomics, metabolomics, cellular, and humoral immunity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•LNP formulated mRNA encoding VZV gE antigen is highly immunogenic in NHP.•mRNA and protein vaccines showed comparable response magnitude and longevity in NHP.•NHP immunogenicity for protein and LAV ...vaccines mirrors human clincal data.
Shingles is a painful, blistering rash caused by reactivation of latent varicella-zoster virus (VZV) and most frequently occurs in elderly and immunocompromised individuals. Currently, two approved vaccines for the prevention of shingles are on the market, a live attenuated virus vaccine ZOSTAVAX® (Merck & Co., Inc., Kenilworth, NJ, USA) and an AS01B adjuvanted subunit protein vaccine Shingrix™ (Glaxo Smith Kline, Rockville, MD, USA). Human clinical immunogenicity and vaccine efficacy data is available for these two benchmark vaccines, offering a unique opportunity for comparative analyses with novel vaccine platforms and animal model translatability studies.
The studies presented here utilized non-human primates (NHP) to evaluate humoral and cellular immune response by three vaccine modalities: the new platform of lipid nanoparticle (LNP) formulated mRNA encoding VZV gE antigen (VZV gE mRNA/LNP) as compared with well-established platforms of live attenuated VZV (VZV LAV) and adjuvanted VZV gE subunit protein (VZV gE protein/adjuvant). The magnitude of response to vaccination with a single 100–200 μg mRNA dose or two 50 μg mRNA doses of VZV gE mRNA/LNP were comparable to two 50 μg protein doses of VZV gE protein/adjuvant, suggesting the VZV gE mRNA/LNP platform has the potential to elicit a robust immune response, and both modalities generated markedly higher responses than VZV LAV. Additionally, the slopes of decay for VZV-specific antibody titers were roughly similar across all three vaccines, indicating the magnitude of peak immunogenicity was the driving force in determining immune response longevity. Finally, vaccine-induced immunogenicity with VZV LAV and VZV gE protein/adjuvant in NHP closely resembled human clinical trials immune response data for ZOSTAVAX® and Shingrix™, helping to validate NHP as an appropriate preclinical model for evaluating these vaccines.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection in infants, the elderly and in immunosuppressed populations. The vast majority of neutralizing antibodies ...isolated from human subjects target the RSV fusion (F) glycoprotein, making it an attractive target for the development of vaccines and therapeutic antibodies. Currently, Synagis® (palivizumab) is the only FDA approved antibody drug for the prevention of RSV infection, and there is a great need for more effective vaccines and therapeutics. Phage display is a powerful tool in antibody discovery with the advantage that it does not require samples from immunized subjects. In this study, Morphosys HuCAL GOLD® phage libraries were used for panning against RSV prefusion and postfusion F proteins. Panels of human monoclonal antibodies (mAbs) against RSV F protein were discovered following phage library panning and characterized. Antibodies binding specifically to prefusion or postfusion F proteins and those binding both conformations were identified. 3B1 is a prototypic postfusion F specific antibody while 2E1 is a prototypic prefusion F specific antibody. 2E1 is a potent broadly neutralizing antibody against both RSV A and B strains. Epitope mapping experiments identified a conformational epitope spanning across three discontinuous sections of the RSV F protein, as well as critical residues for antibody interaction.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The RSV Fusion (F) protein is a target for neutralizing antibody responses and is a focus for vaccine discovery; however, the process of RSV entry requires F to adopt a metastable prefusion form and ...transition to a more stable postfusion form, which displays less potent neutralizing epitopes. mRNA vaccines encode antigens that are translated by host cells following vaccination, which may allow conformational transitions similar to those observed during natural infection to occur. Here we evaluate a panel of chemically modified mRNA vaccines expressing different forms of the RSV F protein, including secreted, membrane associated, prefusion-stabilized, and non-stabilized structures, for conformation, immunogenicity, protection, and safety in rodent models. Vaccination with mRNA encoding native RSV F elicited antibody responses to both prefusion- and postfusion-specific epitopes, suggesting that this antigen may adopt both conformations in vivo. Incorporating prefusion stabilizing mutations further shifts the immune response toward prefusion-specific epitopes, but does not impact neutralizing antibody titer. mRNA vaccine candidates expressing either prefusion stabilized or native forms of RSV F protein elicit robust neutralizing antibody responses in both mice and cotton rats, similar to levels observed with a comparable dose of adjuvanted prefusion stabilized RSV F protein. In contrast to the protein subunit vaccine, mRNA-based vaccines elicited robust CD4+ and CD8+ T-cell responses in mice, highlighting a potential advantage of the technology for vaccines requiring a cellular immune response for efficacy.
Human metapneumovirus (hMPV) belongs to the Pneumoviridae family and is closely related to respiratory syncytial virus (RSV). The surface fusion (F) glycoprotein mediates viral fusion and is the ...primary target of neutralizing antibodies against hMPV. Here we report 113 hMPV-F specific monoclonal antibodies (mAbs) isolated from memory B cells of human donors. We characterize the antibodies' germline usage, epitopes, neutralization potencies, and binding specificities. We find that unlike RSV-F specific mAbs, antibody responses to hMPV F are less dominant against the apex of the antigen, and the majority of the potent neutralizing mAbs recognize epitopes on the side of hMPV F. Furthermore, neutralizing epitopes that differ from previously defined antigenic sites on RSV F are identified, and multiple binding modes of site V and II mAbs are discovered. Interestingly, mAbs that bind preferentially to the unprocessed prefusion F show poor neutralization potency. These results elucidate the immune recognition of hMPV infection and provide novel insights for future hMPV antibody and vaccine development.
Follicular helper T (Tfh) cells promote, whereas follicular regulatory T (Tfr) cells restrain, germinal center (GC) reactions. However, the precise roles of these cells in the complex GC reaction ...remain poorly understood. Here, we perturb Tfh or Tfr cells after SARS-CoV-2 spike protein vaccination in mice. We find that Tfh cells promote the frequency and somatic hypermutation (SHM) of Spike-specific GC B cells and regulate clonal diversity. Tfr cells similarly control SHM and clonal diversity in the GC but do so by limiting clonal competition. In addition, deletion of Tfh or Tfr cells during primary vaccination results in changes in SHM after vaccine boosting. Aged mice, which have altered Tfh and Tfr cells, have lower GC responses, presenting a bimodal distribution of SHM. Together, these data demonstrate that GC responses to SARS-CoV-2 spike protein vaccines require a fine balance of positive and negative follicular T cell help to optimize humoral immunity.
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•Tfh and Tfr cells are required for affinity maturation of GC B cells•Tfh and Tfr cells optimize antibody responses to SARS-CoV-2 vaccines•Aged mice have defective GC responses leading to bimodal antibody responses•Tfh/Tfr help balance affinity maturation with clonal diversity in germinal centers
Cavazzoni et al. show that both Tfh and Tfr cells are essential for optimization of germinal center responses to SARS-CoV-2 vaccines. Limiting Tfh cells results in fewer SARS-CoV-2 GC responses and lower affinity maturation, whereas limiting Tfr cells promotes non-antigen-specific GC responses, leading to lower-affinity maturation. Altered Tfh/Tfr responses in aging result in unique bimodal antibody responses.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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