Biology subjects

Moody, M. A.

Publications and source records attributed to Moody, M. A..

16 recordsLinked to original sources

bioRxiv2026

Genetically restricted human antibodies recognize a conserved β-hairpin in postfusion influenza hemagglutinin

A public class of broadly protective, human antibodies (Abs) binds a conserved {beta}-hairpin exposed in the postfusion conformation of influenza virus hemagglutinin (HA). We here describe use of in vitro immunoassays and high-resolution cryogenic electron microscopy analysis of Ab:HA complexes to explain the apparent genetic restriction of these Abs and the wide range of influenza A and B subtypes they recognize. We show that recognition of the {beta}-hairpin epitope requires 1) germline-encoded residues unique to certain alleles of the human immunoglobulin heavy chain gene IGHV1-2, 2) a short (<14-residue) HCDR3 to avoid steric clash with HA, and 3) several Ab light chain residues that are germline-encoded by various IGLV2-family genes or IGLV7-46. Despite the genetic restrictions, the capacity to make {beta}-hairpin Abs is widespread among humans. We recovered examples of these Abs from 14 genetically unrelated donors, and a previously reported analysis of the IGHV genotypes of ~2,500 individuals sampled from major ethnic populations estimates that >75% of people have the necessary IGHV1-2 alleles to make these Abs. We conclude that an immunogen that displays the {beta}-hairpin epitope might reliably elicit broadly protective influenza antibodies in most humans.

immunology↗

bioRxiv2026

Elicitation of stem-directed antibodies in rhesus macaques by a conventional hemagglutinin immunogen

Because they can bind many strains of influenza, antibodies targeting the hemagglutinin (HA) stem have been attractive targets for vaccine development. Many monoclonal antibodies (mAbs) directed at the HA stem have been isolated from humans, and these mAbs have mediated broad protection in animal models. We describe here HA stem-directed mAbs isolated from rhesus macaques immunized with an "ordinary" H1 HA trimer. All immunized rhesus macaques developed high serum titers with broad reactivity to diverse H1N1 and H5N1 viruses, and 7 isolated mAbs strongly blocked canonical stem antibody CR6261 binding to H1. MAb DH726.1 robustly protected mice from lethal challenge with H1N1 and H5N1 viruses, and cryo-EM showed the binding footprint overlapped that of some human mAbs. These findings suggest that vaccination with the standard, trimeric HA immunogens may be sufficient to elicit stem antibodies at titers adequate to protect against zoonotic H5N1 influenza. In BriefEfforts to achieve broad influenza protection have largely emphasized increasingly sophisticated immunogen designs to redirect antibody responses toward conserved epitopes. Here, we show that a single, conventional HA immunogen readily elicits antibodies targeting the conserved HA stem, suggesting that routine influenza vaccination may provide broader protection than previously appreciated. HighlightsO_LIMonovalent HA immunization induces strong, stem-directed immune responses in rhesus macaques C_LIO_LIEpitope on the HA stem confirmed by Cryo-EM C_LIO_LIFc-mediated activation of immune effector cell by rhesus-derived stem mAb C_LIO_LIHA stem-directed antibody protects mice against H1N1 and H5N1 viruses C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=193 SRC="FIGDIR/small/738984v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@1535b59org.highwire.dtl.DTLVardef@192422dorg.highwire.dtl.DTLVardef@136b3d5org.highwire.dtl.DTLVardef@586fd4_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2026

Functional Convergence of Genetically Diverse B-Cell Receptors in Simian-HIV Infected Rhesus Macaques

Germline-targeting or lineage-design vaccine strategies are being used to induce HIV broadly neutralizing antibody (bnAb) responses. These strategies assume that genetically diverse individuals respond similarly to the same immunogen by mobilizing comparable germline precursors, although outcomes vary across bnAb epitopes. Here we explored this premise using a simian-HIV infection model in rhesus macaques. Antigen-unbiased Env- reactive B-cell populations were profiled, followed by systematic analysis of antibody function and B-cell receptor (BCR) genetics. We find that while global Env-reactive B-cell response profiles and antibody functional properties are similar across individuals, underlying BCR genetics are diverse, particularly among non-bnAbs. These results indicate that functional convergence of Env-reactive antibody responses does not necessarily require genetic convergence and suggest that specific germline-targeting may not be an absolute prerequisite for successful vaccine design. These findings support an epitope-focused framework in which bnAb epitopes are engineered to enhance population-level immunogenicity, with potential applicability to other challenging pathogens.

immunology↗

bioRxiv2025

Sequence variability of BamA and FadL candidate vaccinogens suggests divergent evolutionary paths of Treponema pallidum outer membrane proteins

Knowledge of Treponema pallidum subspecies pallidum (TPA) outer membrane protein (OMP) sequence variability is essential for understanding spirochete proliferation within endemic populations as well as design of a globally effective syphilis vaccine. Our group has identified extracellular loops (ECLs) of TPA BamA (TP0326) and members of the FadL family (TP0548, TP0856, TP0858, TP0859, and TP0865) as potential components of a multivalent vaccine cocktail. As part of a consortium to explore TPA strain diversity, we mapped the variability of BamA and FadL orthologs in 186 TPA strains from Malawi, China and Colombia onto predicted 3D structures. The 186 genomes fell into eight subclades (five Nichols-, three SS14-lineage) with substantial geographic restriction. Single nucleotide variants accounted for the large majority of proteoforms, with variability notably higher within the Nichols-lineage strains. Most mutations were in regions of the proteins predicted to be extracellular and harboring B cell epitopes. We observed a striking difference in the degree of variability between the six OMPs, suggesting that these proteins are following divergent evolutionary paths. Concatenation of OMP sequences recapitulated the phylogenetic structure of the TPA strains, effectively segregating within clades and largely clustering by subclades. Lastly, we noted that BamA and FadL candidate ECL vaccinogens previously shown to elicit antibodies that kill treponemes during in vitro cultivation are well conserved. Taken as a whole, our study establishes a structural-phylogenetic approach for analyzing the forces shaping the host-pathogen interface in syphilis within endemic populations while informing selection of vaccine targets. IMPORTANCESyphilis remains a major global health concern, reinforcing the need for a safe and effective vaccine. Understanding the variability of TPA OMPs is essential for tracking pathogen evolution and informing vaccine design. Here, we analyzed the variability of six TPA OMPs in 186 strains from Malawi, China, and Colombia, identifying protein-specific evolutionary patterns. Most mutations were localized in extracellular regions and, notably, appeared to correlate with the phylogenetic structure of TPA. Despite OMP heterogeneity, several candidate vaccinogens remained highly conserved, reinforcing their potential as globally effective vaccine targets. Our study establishes a structural-phylogenetic framework for dissecting the forces shaping the host-spirochete interface within endemic populations and provides a foundation for designing a globally effective syphilis vaccine.

microbiology↗

bioRxiv2025

Fluorescence-barcoded cell lines stably expressing membrane-anchored influenza neuraminidases

The discovery of broadly protective antibodies to the influenza virus neuraminidase (NA) has raised interest in NA as a vaccine target. However, recombinant, solubilized tetrameric NA ectodomains are often challenging to express and isolate, hindering the study of anti-NA humoral responses. To address this obstacle, we established a panel of 22 non-adherent cell lines stably expressing native, historical N1, N2, N3, N9, and NB NAs anchored on the cell surface. The cell lines are barcoded with fluorescent proteins, enabling high-throughput, 16-plex analyses of antibody binding with commonly available flow cytometers. The cell lines were at least as efficient as a Luminex multiplex binding assay at identifying NA antibodies from a library of unselected clonal IgGs derived from human memory B cells. The cell lines were also useful for measuring the magnitude and breadth of the serum antibody response elicited by experimental infection of rhesus macaques with influenza virus. The membrane-anchored NAs are catalytically active and are compatible with established sialidase activity assays. NA-expressing K530 cell lines therefore represent a useful tool for studying NA immunity and evaluating influenza vaccine efficacy.

immunology↗

bioRxiv2024

Immunodominant extracellular loops of Treponema pallidum FadL outer membrane proteins elicit antibodies with opsonic and growth-inhibitory activities

The global resurgence of syphilis has created a potent stimulus for vaccine development. To identify potentially protective antibodies (Abs) against Treponema pallidum (TPA), we used Pyrococcus furiosus thioredoxin (PfTrx) to display extracellular loops (ECLs) from three TPA outer membrane protein families (outer membrane factors for efflux pumps, eight-stranded {beta}-barrels, and FadLs) to assess their reactivity with immune rabbit serum (IRS). Five ECLs from the FadL orthologs TP0856, TP0858 and TP0865 were immunodominant. Rabbits and mice immunized with these five PfTrx constructs produced ECL-specific Abs that promoted opsonophagocytosis of TPA by rabbit peritoneal and murine bone marrow-derived macrophages at levels comparable to IRS and mouse syphilitic serum. ECL-specific rabbit and mouse Abs also impaired viability, motility, and cellular attachment of spirochetes during in vitro cultivation. The results support the use of ECL-based vaccines and suggest that ECL-specific Abs promote spirochete clearance via Fc receptor-independent as well as Fc receptor-dependent mechanisms. Author SummaryThe resurgence of syphilis emphasizes the critical need for vaccine development against Treponema pallidum (TPA). Research utilizing immune rabbit serum (IRS) suggests that an effective syphilis vaccine should induce "functional" antibodies (Abs) capable of enhancing the opsonophagocytosis of treponemes by activated macrophages. Structural models of TPA outer membrane proteins (OMPs), specifically the extracellular loops (ECLs), guided the identification of potential vaccine candidates. Antigenic analysis with IRS of individual ECLs from three TPA OMP families scaffolded onto Pyrococcus furiosus thioredoxin (PfTrx) revealed five FadL antigenic ECLs. Immunization with immunodominant ECL antigens elicited robust ECL-specific Abs, demonstrating functional opsonic activity in the opsonophagocytosis assays. Furthermore, these Abs effectively inhibited the growth inhibition of in vitro-cultivated TPA in both rabbit and mouse models. Our findings underscore the value of antigenic analysis in identifying promising TPA OMP ECL vaccine targets and highlight the multifaceted protective capacity of ECL Abs against TPA. This approach also extends to identifying potential OMP vaccinogens in other bacterial pathogens, offering valuable insights for broader vaccine development strategies.

immunology↗

bioRxiv2023

Use of Epivolve phage display to generate a monoclonal antibody with opsonic activity directed against a subdominant epitope on extracellular loop 4 of Treponema pallidum BamA (TP0326)

Syphilis, a sexually transmitted infection caused by the spirochete Treponema pallidum (Tp), is resurging globally. Opsonic antibodies (Abs) targeting surface-exposed epitopes of the spirochetes outer membrane proteins (OMPs) are believed to promote macrophage-mediated clearance of the bacterium during infection and are presumed to be key to vaccine development. Tps repertoire of outer membrane proteins includes BamA ({beta}-barrel assembly machinery subunit A/TP0326), the central component of the molecular machine that inserts newly exported OMP precursors into the OM lipid bilayer. BamA is a bipartite protein consisting of an 18-stranded {beta}-barrel with nine extracellular loops (ECLs) and five periplasmic POTRA (polypeptide transport-associated) domains. Antisera directed against BamA ECL4 promote internalization of Tp by rabbit peritoneal macrophages. Herein, we employed a novel two-stage, phage display strategy, termed "Epivolve" (for epitope evolution), to generate five site-directed murine monoclonal Abs (mAbs) targeting a centrally located peptide (S2) of BamA ECL4. Each of the five mAbs demonstrated reactivity by immunoblotting and ELISA to nanogram amounts of BamA ECL4 displayed by a Pyrococcus furiosus thioredoxin (PfTrx) scaffold (PfTrxBamA/ECL4). One mAb containing a unique amino acid sequence in both light and heavy chains showed activity in an opsonophagocytosis assay employing murine bone marrow-derived macrophages. Mice and rabbits hyperimmunized with PfTrxBamA/ECL4 produced opsonic antisera that strongly recognized the ECL presented in a heterologous scaffold and overlapping ECL4 peptides including S2. In contrast, Abs generated during Tp infection of mice and rabbits poorly recognized the peptides, indicating that S2 contains a subdominant epitope. Epivolve, which circumvents the natural immune response, can be utilized for the generation of mAbs that target subdominant opsonic epitopes in ECLs of Tp OMPs.

immunology↗

bioRxiv2023

Vaccine induction of CD4-mimicking broadly neutralizing antibody precursors in macaques

The CD4 binding site (CD4bs) is a conserved epitope on HIV-1 envelope (Env) that can be targeted by protective broadly neutralizing antibodies (bnAbs). HIV-1 vaccines have not elicited CD4bs bnAbs for many reasons, including the CD4bs is occluded by glycans, immunogen expansion of appropriate naive B cells, and selection of functional antibody mutations. Here, we demonstrate immunization of macaques with a CD4bs-targeting immunogen elicits neutralizing bnAb precursors with structural and genetic features of CD4-mimicking bnAbs. Structures of the CD4bs nAbs bound to HIV-1 Env demonstrated binding angles similar to human bnAbs and heavy chain second complementarity determining region-dependent binding characteristic of all known human CD4-mimicking bnAbs. Macaque nAbs were derived from variable and joining gene segments orthologous to the genes of human VH1-46-class bnAbs. This vaccine study initiated the B cells from which derive CD4bs bnAbs in primates, accomplishing the key first step in development of an effective HIV-1 vaccine.

immunology↗

bioRxiv2022

Infant antibody repertoires during the first two years of influenza vaccination

The first encounter with influenza virus biases later immune responses. This "immune imprinting", formerly from infection within a few years of birth, is in the U.S. now largely from immunization with a quadrivalent, split vaccine (IIV4). In a pilot study of IIV4 imprinting, we characterized, by single-B-cell cultures, NextGen sequencing, and plasma antibody proteomics, the primary antibody responses to influenza in two infants during their first two years of seasonal influenza vaccination. One infant, who received only a single vaccination in Year 1, contracted an influenza B (IBV) infection between the two years, allowing us to compare imprinting by infection and vaccination. That infant had a shift in hemagglutinin (HA)-reactive B-cell specificity from largely influenza A (IAV)-specific in Year 1 to IBV-specific in Year 2, both before and after vaccination. HA-reactive B cells from the other infant maintained a more evenly distributed specificity. In Year 2, class-switched HA-specific B cell IGHV somatic hypermutation (SHM) levels reached average levels seen in adults. The HA-reactive plasma antibody repertoires of both infants comprised a relatively small number of antibody clonotypes, with one or two very abundant clonotypes. Thus, after the Year 2 boost, both infants had overall B cell profiles that resembled those of adult controls. ImportanceInfluenza virus is a moving target for the immune system. Variants emerge that escape protection from antibodies elicited by a previously circulating variant ("antigenic drift"). The immune system usually responds to a drifted influenza virus by mutating existing antibodies rather than by producting entirely new ones. Thus, immune memory of the earliest influenza exposure has a major influence on later responses to infection or vaccination ("immune imprinting"). In the many studies of influenza immunity in adult subjects, imprinting has been from an early infection, since only in the past two decades have infants received influenza immunizations. The work reported in this paper is a pilot study of imprinting in two infants by the flu vaccine, which they received before experiencing an influenza infection. The results suggest that a quadrivalent (four-subtype) vaccine may provide an immune imprint less dominated by one subtype than does a monovalent infection.

immunology↗

bioRxiv2022

Disease diagnostics using machine learning of immune receptors

Clinical diagnosis typically incorporates physical examination, patient history, and various laboratory tests and imaging studies, but makes limited use of the human systems own record of antigen exposures encoded by receptors on B cells and T cells. We analyzed immune receptor datasets from 593 individuals to develop MAchine Learning for Immunological Diagnosis (Mal-ID), an interpretive framework to screen for multiple illnesses simultaneously or precisely test for one condition. This approach detects specific infections, autoimmune disorders, vaccine responses, and disease severity differences. Human-interpretable features of the model recapitulate known immune responses to SARS-CoV-2, Influenza, and HIV, highlight antigen-specific receptors, and reveal distinct characteristics of Systemic Lupus Erythematosus and Type-1 Diabetes autoreactivity. This analysis framework has broad potential for scientific and clinical interpretation of human immune responses.

immunology↗

bioRxiv2021

Different adjuvanted pediatric HIV envelope vaccines induced distinct plasma antibody responses despite similar B cell receptor repertoires in infant rhesus macaques.

Different HIV vaccine regimens elicit distinct plasma antibody responses in both human and nonhuman primate models. Previous studies in human and non-human primate infants showed that adjuvants influenced the quality of plasma antibody responses induced by pediatric HIV envelope vaccine regimens. We recently reported that use of the 3M052-SE adjuvant and longer intervals between vaccinations are associated with higher magnitude of antibody responses in infant rhesus macaques. However, the impact of different adjuvants in HIV vaccine regimens on the developing infant B cell receptor (BCR) repertoire has not been studied. This study evaluated whether pediatric HIV envelope vaccine regimens with different adjuvants induced distinct antigen-specific memory B cell repertoires and whether specific immunoglobulin (Ig) immunogenetic characteristics are associated with higher magnitude of plasma antibody responses in vaccinated infant rhesus macaques. We utilized archived preclinical pediatric HIV vaccine studies PBMCs and tissue samples from 19 infant rhesus macaques immunized either with (i) HIV Env protein with a squalene adjuvant, (ii) MVA-HIV and Env protein coadministered using a 3-week interval, (iii) MVA-HIV prime/ protein boost with an extended 6-week interval between immunizations, or (iv) with HIV Env administered with 3M-052-SE adjuvant. Frequencies of vaccine-elicited HIV Env-specific memory B cells from PBMCs and tissues were similar across vaccination groups (frequency range of 0.06-1.72%). There was no association between vaccine-elicited antigen-specific memory B cell frequencies and plasma antibody titer or avidity. Moreover, the epitope specificity and Ig immunogenetic features of vaccine-elicited monoclonal antibodies did not differ between the different vaccine regimens. These data suggest that pediatric HIV envelope vaccine candidates with different adjuvants that previously induced higher magnitude and quality of plasma antibody responses in infant rhesus macaques were not driven by distinct antigen-specific memory BCR repertoires.

immunology↗

bioRxiv2021

Frequent development of broadly neutralizing antibodies in early life in a large cohort of HIV-infected children

Recent studies conducted in small cohorts of children have indicated that broadly neutralizing antibodies (bnAbs) may develop earlier after HIV infection compared to adults. To define the frequency and kinetics of bnAb responses in a larger pediatric cohort, we evaluated plasma from 212 ART-naive, children living with HIV aged 1 to 3 years. Neutralization breadth and potency was assessed using a panel of 10 tier-2 viruses and compared to those of adults with chronic HIV. Further, the magnitude, epitope specificity and IgG subclass distribution of Env-specific antibodies were also assessed using a binding antibody multiplex assay. We found that 1-year-old children demonstrated neutralization breadth comparable to that of chronically-infected adults, and breadth continued to increase with age such that the pediatric cohort overall exhibited significantly greater neutralization breadth than adults (p= 0.014). Similarly, binding antibody responses increased with age, and the levels in 2 to 3 year-old children were comparable to those of adults. Overall, there was no significant difference in antibody specificities or IgG subclass distribution between the pediatric and adult cohorts. Interestingly, the neutralization activity was mapped to a single epitope (CD4 binding site, V2 or V3 glycans) in only 5 of 38 pediatric broadly neutralizing samples, suggesting a polyclonal neutralization response may develop in most children. These results contribute to a growing body of evidence suggesting that the early life immune system may present advantages for the development of an effective HIV vaccine. Author summaryUnderstanding the development of broadly neutralizing antibodies during natural HIV infection is critical to provide insights for the development of an effective vaccine. In this study, we used a large cohort (n=212) of HIV infected children aged 1-3 years old to define the frequency and kinetics of broad neutralization in comparison to adults with chronic HIV. We also evaluated the magnitude and epitope specificity of HIV Env-specific antibodies in children and adults. We observed that both the binding and neutralizing antibody responses increased with age. However, by one year of age, children had neutralization breadth comparable to that of chronically infected adults; and overall, 1-3 year-old children demonstrated higher neutralization breadth than adults. Only slight differences in epitope-specificity and IgG subclass distribution were observed between children and adults, suggesting that these factors are not major contributors to the observed age-related difference in neutralization breadth. The epitope specificity of the neutralizing antibodies could not be mapped in the majority of children, suggesting that their response may be polyclonal. Our study contributes to the body of work indicating a potential advantage of the early life immune system for the elicitation of broad neutralization.

immunology↗

bioRxiv2021

The functions of SARS-CoV-2 neutralizing and infection-enhancing antibodies in vitro and in mice and nonhuman primates

SARS-CoV-2 neutralizing antibodies (NAbs) protect against COVID-19. A concern regarding SARS-CoV-2 antibodies is whether they mediate disease enhancement. Here, we isolated NAbs against the receptor-binding domain (RBD) and the N-terminal domain (NTD) of SARS-CoV-2 spike from individuals with acute or convalescent SARS-CoV-2 or a history of SARS-CoV-1 infection. Cryo-electron microscopy of RBD and NTD antibodies demonstrated function-specific modes of binding. Select RBD NAbs also demonstrated Fc receptor-{gamma} (Fc{gamma}R)-mediated enhancement of virus infection in vitro, while five non-neutralizing NTD antibodies mediated Fc{gamma}R-independent in vitro infection enhancement. However, both types of infection-enhancing antibodies protected from SARS-CoV-2 replication in monkeys and mice. Nonetheless, three of 31 monkeys infused with enhancing antibodies had higher lung inflammation scores compared to controls. One monkey had alveolar edema and elevated bronchoalveolar lavage inflammatory cytokines. Thus, while in vitro antibody-enhanced infection does not necessarily herald enhanced infection in vivo, increased lung inflammation can occur in SARS-CoV-2 antibody-infused macaques.

immunology↗

bioRxiv2020

Recapitulation of HIV-1 Env-Antibody Coevolution in Macaques Leading to Neutralization Breadth

Neutralizing antibodies elicited by HIV-1 coevolve with viral Envs in distinctive patterns, in some cases acquiring substantial breadth. Here we show that primary HIV-1 Envs, when expressed by simian-human immunodeficiency viruses in rhesus macaques, elicited patterns of Env-antibody coevolution strikingly similar to those in humans. This included conserved immunogenetic, structural and chemical solutions to epitope recognition and precise Env-amino acid substitutions, insertions and deletions leading to virus persistence. The structure of one rhesus antibody, capable of neutralizing 49% of a 208-strain panel, revealed a V2-apex mode of recognition like that of human bNAbs PGT145/PCT64-35M. Another rhesus antibody bound the CD4-binding site by CD4 mimicry mirroring human bNAbs 8ANC131/CH235/VRC01. Virus-antibody coevolution in macaques can thus recapitulate developmental features of human bNAbs, thereby guiding HIV-1 immunogen design. One sentence summaryVirus-antibody coevolution in rhesus macaques recapitulates developmental features of human antibodies.

immunology↗

bioRxiv2019

Maternal alum-adjuvanted recombinant HIV Env vaccine does not enhance autologous virus neutralization in HIV-infected pregnant women

Preventive strategies beyond ART will be required to end the pediatric HIV epidemic. A maternal vaccine capable of boosting neutralizing antibody (nAb) responses against circulating viruses in HIV-infected pregnant women could effectively decrease mother-to-child transmission of HIV. However, it is not known if an HIV envelope (Env) vaccine administered to infected pregnant women can enhance autologous virus neutralization. Here, we assessed autologous virus nAb responses in maternal plasma samples obtained from AIDS Vaccine Evaluation Group (AVEG) Protocols 104 and 102, historical Phase I safety and immunogenicity trials of recombinant HIV Env subunit vaccines in HIV-infected pregnant women (NCT00001041). AVEG 104 participants were randomized to receive 300 {micro}g Env subunit MN recombinant gp120 with alum adjuvant or alum alone. AVEG 102 participants were randomized to receive 640 {micro}g Env subunit recombinant gp160 or placebo. HIV Env-specific maternal plasma binding and neutralizing responses were characterized before and after vaccination in 15 AVEG 104 (n=10 vaccinee, n=5 placebo) and 2 AVEG 102 (n=1 vaccinee, n=1 placebo) participants. Single genome amplification (SGA) was used to obtain HIV env gene sequences from autologous viruses for pseudovirus production in pre- and post-vaccination plasma of HIV-infected pregnant vaccinees (n=6 gp120, n=1 gp160) and placebo recipients (n=3). We detected an increase in MN gp120-specific IgG binding in the vaccinee group between the first immunization visit and the last visit at delivery (p=0.027, 2-sided Wilcoxon test). However, no difference was observed in the neutralization potency of maternal plasma collected at delivery against autologous viruses isolated from early or late pregnancy. Thus, maternal vaccination with gp120/160 did not boost maternal autologous virus nAb responses. Immunization strategies capable of more potent B cell stimulation will likely be required to effectively boost autologous virus nAb responses in pregnant women and synergize with ART to further reduce infant HIV infections. HighlightsO_LIPrior maternal HIV Env vaccine trial did not assess autologous virus neutralization C_LIO_LICirculating viruses isolated from mothers were tested against autologous plasma C_LIO_LIMaternal vaccination with HIV Env gp120/160 increased MN gp120-specific IgG binding C_LIO_LIMaternal HIV Env vaccine regimen did not boost autologous virus neutralization C_LIO_LIMore potent B cell stimulation will be required to elicit autologous nAb responses C_LI

immunology↗

bioRxiv2019

Boosting with ALVAC-HIV and AIDSVAX B/E enhances Env constant region 1 and 2 antibody-dependent cellular cytotoxicity

Induction of protective antibodies is a critical goal of HIV-1 vaccine development. One strategy is to induce non-neutralizing antibodies that kill virus-infected cells as these antibody specificities have been implicated in slowing HIV-1 disease progression and in protection. HIV-1 Env constant region 1 and 2 (C1C2) antibodies frequently contain potent antibody dependent cellular cytotoxicity (ADCC) making them a vaccine target. Here we explore the effect of delayed and repetitive boosting of RV144 vaccinee recipients with ALVAC/AIDSVAX B/E on the C1C2-specific antibody repertoire. It was found that boosting increased clonal lineage specific ADCC breadth and potency. A ligand crystal structure of a vaccine-induced broad and potent ADCC-mediating C1C2-specific antibody showed that it bound a highly conserved Env gp120 epitope. Thus, rationally designed boosting strategies to affinity mature these type of IgG C1C2-specific antibody responses may be one method by which to make an improved HIV vaccine with higher efficacy than seen in the RV144 trial.\n\nSignificanceOver one million people become infected with HIV-1 each year making the development of an efficacious HIV-1 vaccine an important unmet medical need. The RV144 human HIV-1 vaccine-regimen is the only HIV-1 clinical trial to date to demonstrate vaccine-efficacy. An area of focus has been on identifying ways by which to improve upon RV144 vaccine-efficacy. The RV305 HIV-1 vaccine-regimen was a follow-up boost of RV144 vaccine-recipients that occurred 6-8 years after the conclusion of RV144. Our studies focused on the effect of delayed boosting in humans on the vaccine-induced antibody repertoire. It was found that boosting with a HIV-1 Env vaccine increased antibody-mediated effector function potency and breadth.

immunology↗