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A heterologous Ad26/MVA vaccine was given prior to an analytic treatment interruption (ATI) in people living with HIV-1 (mainly CRF01_AE) who initiated antiretroviral treatment (ART) during acute HIV-1. We investigate the impact of Ad26/MVA vaccination on antibody (Ab)-mediated immune responses and their effect on time to viral rebound. The vaccine mainly triggers vaccine-matched binding Abs while, upon viral rebound post ATI, infection-specific CRF01_AE binding Abs increase in all participants. Binding Abs are not associated with time to viral rebound. The Ad26/MVA mosaic vaccine profile consists of correlated non-CRF01_AE binding Ab and Fc effector features, with strong Ab-dependent cellular phagocytosis (ADCP) responses. CRF01_AE-specific ADCP responses (measured either prior to or post ATI) are significantly higher in individuals with delayed viral rebound. Our results suggest that vaccines eliciting cross-reactive responses with circulating viruses in a target population could be beneficial and that ADCP responses may play a role in viral control post treatment interruption., Competing Interests: Declaration of interests The views expressed are those of the authors and should not be construed to represent the positions of the US Army, the Department of Defense, the Department of Health and Human Services, or the Henry M. Jackson Foundation for the Advancement of Military Medicine. D.J.S., F.L.T., H.S., and M.G.P. were employees of Janssen Vaccines & Prevention at the time the study was conducted and still hold stock in Johnson & Johnson. M.G.P. is an employee of Janssen Vaccines & Prevention and holds stock in Johnson & Johnson. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript., (Copyright © 2024 Henry M Jackson Foundation for the Advancement of Military Medicine, Inc. Published by Elsevier Inc. All rights reserved.)

Zika virus (ZIKV) is an emerging pathogen that causes devastating congenital defects. The overlapping epidemiology and immunologic cross-reactivity between ZIKV and dengue virus (DENV) pose complex challenges to vaccine design, given the potential for antibody-dependent enhancement of disease. Therefore, classification of ZIKV-specific antibody targets is of notable value. From a ZIKV-infected rhesus macaque, we identify ZIKV-reactive B cells and isolate potent neutralizing monoclonal antibodies (mAbs) with no cross-reactivity to DENV. We group these mAbs into four distinct antigenic groups targeting ZIKV-specific cross-protomer epitopes on the envelope glycoprotein. Co-crystal structures of representative mAbs in complex with ZIKV envelope glycoprotein reveal envelope-dimer epitope and unique dimer-dimer epitope targeting. All four specificities are serologically identified in convalescent humans following ZIKV infection, and representative mAbs from all four groups protect against ZIKV replication in mice. These results provide key insights into ZIKV-specific antigenicity and have implications for ZIKV vaccine, diagnostic, and therapeutic development., Competing Interests: Declaration of interests S.J.K., V.D., G.D., K.M., N.M., D.H.B., M.G.J., R.S.S., and R.G.J. are named inventors on a PCT patent application WO 2019/209974 describing ZIKV neutralizing antibodies and their use. D.H.B. has received grants from Novavax and personal fees from IGM Biosciences. M.H., A.A., E.D., and B.J.D. are employees of Integral Molecular. B.J.D. is also a shareholder of the company., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

The SARS-CoV-2 Omicron variant of concern (VoC) and its sublineages contain 31-36 mutations in spike and escape neutralization by most therapeutic antibodies. In a pseudovirus neutralization assay, 66 of the nearly 400 candidate therapeutics in the Coronavirus Immunotherapeutic Consortium (CoVIC) panel neutralize Omicron and multiple Omicron sublineages. Among natural immunoglobulin Gs (IgGs), especially those in the receptor-binding domain (RBD)-2 epitope community, nearly all Omicron neutralizers recognize spike bivalently, with both antigen-binding fragments (Fabs) simultaneously engaging adjacent RBDs on the same spike. Most IgGs that do not neutralize Omicron bind either entirely monovalently or have some (22%-50%) monovalent occupancy. Cleavage of bivalent-binding IgGs to Fabs abolishes neutralization and binding affinity, with disproportionate loss of activity against Omicron pseudovirus and spike. These results suggest that VoC-resistant antibodies overcome mutagenic substitution via avidity. Hence, vaccine strategies targeting future SARS-CoV-2 variants should consider epitope display with spacing and organization identical to trimeric spike., Competing Interests: Declaration of interests C.C.B. and M.D.A. are inventors on the patent application PCT/US21/33454, which covers the version of ACE2-Ig used in this study. The patent application is assigned to Emmune, Inc. M.D.A., C.C.B., and J.M.T. own stock in Emmune, Inc. Y.G. is co-founder and shareholder in Antibody BioPharm, Inc., and ChangYuan FuNeng (Shanghai) Life Technology Co., Ltd. L.Y. and Y.G. have filed patent applications on related COVID-19 antibodies. P.D.C., J.T., and H.C. are inventors on several of the antibodies described in this study., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

The need for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) next-generation vaccines has been highlighted by the rise of variants of concern (VoCs) and the long-term threat of emerging coronaviruses. Here, we design and characterize four categories of engineered nanoparticle immunogens that recapitulate the structural and antigenic properties of the prefusion SARS-CoV-2 spike (S), S1, and receptor-binding domain (RBD). These immunogens induce robust S binding, ACE2 inhibition, and authentic and pseudovirus neutralizing antibodies against SARS-CoV-2. A spike-ferritin nanoparticle (SpFN) vaccine elicits neutralizing titers (ID 50 > 10,000) following a single immunization, whereas RBD-ferritin nanoparticle (RFN) immunogens elicit similar responses after two immunizations and also show durable and potent neutralization against circulating VoCs. Passive transfer of immunoglobulin G (IgG) purified from SpFN- or RFN-immunized mice protects K18-hACE2 transgenic mice from a lethal SARS-CoV-2 challenge. Furthermore, S-domain nanoparticle immunization elicits ACE2-blocking activity and ID 50 neutralizing antibody titers >2,000 against SARS-CoV-1, highlighting the broad response elicited by these immunogens., Competing Interests: Declaration of interests M.G.J. and K.M. are named as inventors on international patent application WO/2021/178971 A1 entitled “Vaccines against SARS-CoV-2 and other coronaviruses.” M.G.J. is named as an inventor on international patent application WO/2018/081318 and U.S. patent 10,960,070 entitled “Prefusion coronavirus spike proteins and their use.” Z.B. is named as an inventor on U.S. patent 10,434,167 entitled “Non-toxic adjuvant formulation comprising a monophosphoryl lipid A (MPLA)-containing liposome composition and a saponin.” Z.B. and G.R.M. are named as inventors on U.S. patent application 16/607,917 entitled “Compositions and methods for vaccine delivery.” M.S.D. is a consultant for Inbios, Vir Biotechnology, Fortress Biotech, and Carnival Corporation and on the scientific advisory boards of Moderna and Immunome. The Diamond laboratory has received funding support from sponsored research agreements from Moderna, Vir Biotechnology, Kaleido, and Emergent BioSolutions. S.R., P.M.M., and M.T.E. are employees of AstraZeneca and currently hold AstraZeneca stock or stock options. Z.B. is currently employed at Pfizer., (Copyright © 2021. Published by Elsevier Inc.)

The V1V2 region of the HIV-1 envelope is the target of several broadly neutralizing antibodies (bNAbs). Antibodies to V1V2 elicited in the RV144 clinical trial correlated with a reduced risk of HIV infection, but these antibodies were without broad neutralizing activity. Antibodies targeting V1V2 also correlated with a reduced viral load in immunized macaques challenged with simian immunodeficiency virus (SIV) or simian/human immunodeficiency virus (SHIV). To focus immune responses on V1V2, we engrafted the native, glycosylated V1V2 domain onto five different multimeric scaffold proteins and conducted comparative immunogenicity studies in macaques. Vaccinated macaques developed high titers of plasma and mucosal antibodies that targeted structurally distinct V1V2 epitopes. Plasma antibodies displayed limited neutralizing activity but were functionally active for ADCC and phagocytosis, which was detectable 1-2 years after immunizations ended. This study demonstrates that multivalent, glycosylated V1V2-scaffold protein immunogens focus the antibody response on V1V2 and are differentially effective at inducing polyfunctional antibodies with characteristics associated with protection., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)