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The HIV-1 envelope glycoprotein (Env) is the sole neutralizing determinant on the surface of the virus. The Env gp120 and gp41 subunits mediate receptor binding and membrane fusion and are generated from the gp160 precursor by cellular furins. This cleavage event is required for viral entry. One approach to generate HIV-1 neutralizing antibodies following immunization is to express membrane-bound Env anchored on the cell-surface by genetic means using the natural HIV gp41 transmembrane (TM) spanning domain. To simplify the process of Env trimer membrane expression we sought to remove the need for Env precursor cleavage while maintaining native-like conformation following genetic expression. To accomplish these objectives, we selected our previously developed 'native flexibly linked' (NFL) stabilized soluble trimers that are both near-native in conformation and cleavage-independent. We genetically fused the NFL construct to the HIV TM domain by using a short linker or by restoring the native membrane external proximal region, absent in soluble trimers, to express the full HIV Env ectodomain on the plasma membrane. Both forms of cell-surface NFL trimers, without and with the MPER, displayed favorable antigenic profiles by flow cytometry when expressed from plasmid DNA or mRNA. These results were consistent with the presence of well-ordered cell surface native-like trimeric Env, a necessary requirement to generate neutralizing antibodies by vaccination. Inoculation of rabbits with mRNA lipid nanoparticles (LNP) expressing membrane-bound stabilized HIV Env NFL trimers generated tier 2 neutralizing antibody serum titers in immunized animals. Multiple inoculations of mRNA LNPs generated similar neutralizing antibody titers compared to immunizations of matched NFL soluble proteins in adjuvant. Given the recent success of mRNA vaccines to prevent severe COVID, these are important developments for genetic expression of native-like HIV Env trimers in animals and potentially in humans.
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Vacunas contra el SIDA , Anticuerpos Neutralizantes , Anticuerpos Anti-VIH , VIH-1 , Nanopartículas , ARN Mensajero , Productos del Gen env del Virus de la Inmunodeficiencia Humana , Animales , Anticuerpos Anti-VIH/inmunología , VIH-1/inmunología , Anticuerpos Neutralizantes/inmunología , Humanos , Productos del Gen env del Virus de la Inmunodeficiencia Humana/inmunología , Productos del Gen env del Virus de la Inmunodeficiencia Humana/genética , Vacunas contra el SIDA/inmunología , Conejos , ARN Mensajero/inmunología , ARN Mensajero/genética , Lípidos/inmunología , Multimerización de Proteína , Infecciones por VIH/inmunología , Infecciones por VIH/virología , Infecciones por VIH/prevención & control , Femenino , LiposomasRESUMEN
Many individuals struggle to regulate their own consumption of food. Beginning with general theories of self-control, we review psychological factors that have been shown to influence the regulation of eating, including those related to particular personality variables, such as external eating, restrained eating, and reward sensitivity, as well as situational constraints, including normative influences, emotions, and calorie deprivation. Strategies for the self-control of eating, including reappraisal, effortful inhibition, and various automatic strategies are also reviewed, along with a discussion of the strengths and limitations of historical and contemporary psychological studies investigating food consumption. Whereas extensive examinations of food preferences and body weight have appeared in the psychological literature, we call for more robust research that prioritizes actual eating as the primary dependent measure.
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Cellular and molecular characterization of immune responses elicited by influenza virus infection and seasonal vaccination have informed efforts to improve vaccine efficacy, breadth, and longevity. Here, we use negative stain electron microscopy polyclonal epitope mapping (nsEMPEM) to structurally characterize the humoral IgG antibody responses to hemagglutinin (HA) from human patients vaccinated with a seasonal quadrivalent flu vaccine or infected with influenza A viruses. Our data show that both vaccinated and infected patients had humoral IgGs targeting highly conserved regions on both H1 and H3 subtype HAs, including the stem and anchor, which are targets for universal influenza vaccine design. Responses against H1 predominantly targeted the central stem epitope in infected patients and vaccinated donors, whereas head epitopes were more prominently targeted on H3. Responses against H3 were less abundant, but a greater diversity of H3 epitopes were targeted relative to H1. While our analysis is limited by sample size, on average, vaccinated donors responded to a greater diversity of epitopes on both H1 and H3 than infected patients. These data establish a baseline for assessing polyclonal antibody responses in vaccination and infection, providing context for future vaccine trials and emphasizing the importance of carefully designing vaccines to boost protective responses towards conserved epitopes.
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Immunodominance of antibodies targeting non-neutralizing epitopes and the high level of somatic hypermutation within germinal centers (GCs) required for most HIV broadly neutralizing antibodies (bnAbs) are major impediments to the development of an effective HIV vaccine. Rational protein vaccine design and non-conventional immunization strategies are potential avenues to overcome these hurdles. Here, we report using implantable osmotic pumps to continuously deliver a series of epitope-targeted immunogens to rhesus macaques over the course of six months to prime and elicit antibody responses against the conserved fusion peptide (FP). GC responses and antibody specificities were tracked longitudinally using lymph node fine-needle aspirates and electron microscopy polyclonal epitope mapping (EMPEM), respectively, to show antibody responses to the FP/N611 glycan hole region were primed, although exhibited limited neutralization breadth. Application of cryoEMPEM delineated key residues for on-target and off-target responses that can drive the next round of structure-based vaccine design.
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The development of vaccines and therapeutics that are broadly effective against known and emergent coronaviruses is an urgent priority. We screened the circulating B cell repertoires of COVID-19 survivors and vaccinees to isolate over 9,000 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific monoclonal antibodies (mAbs), providing an expansive view of the SARS-CoV-2-specific Ab repertoire. Among the recovered antibodies was TXG-0078, an N-terminal domain (NTD)-specific neutralizing mAb that recognizes diverse alpha- and beta-coronaviruses. TXG-0078 achieves its exceptional binding breadth while utilizing the same VH1-24 variable gene signature and heavy-chain-dominant binding pattern seen in other NTD-supersite-specific neutralizing Abs with much narrower specificity. We also report CC24.2, a pan-sarbecovirus neutralizing antibody that targets a unique receptor-binding domain (RBD) epitope and shows similar neutralization potency against all tested SARS-CoV-2 variants, including BQ.1.1 and XBB.1.5. A cocktail of TXG-0078 and CC24.2 shows protection in vivo, suggesting their potential use in variant-resistant therapeutic Ab cocktails and as templates for pan-coronavirus vaccine design.
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Anticuerpos Neutralizantes , Anticuerpos Antivirales , COVID-19 , Epítopos , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus , Humanos , SARS-CoV-2/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Anticuerpos Neutralizantes/inmunología , COVID-19/inmunología , COVID-19/virología , Epítopos/inmunología , Anticuerpos Antivirales/inmunología , Anticuerpos Monoclonales/inmunología , Animales , Betacoronavirus/inmunología , RatonesRESUMEN
Influenza B viruses (IBVs) comprise a substantial portion of the circulating seasonal human influenza viruses. Here, we describe the isolation of human monoclonal antibodies (mAbs) that recognized the IBV neuraminidase (NA) glycoprotein from an individual following seasonal vaccination. Competition-binding experiments suggested the antibodies recognized two major antigenic sites. One group, which included mAb FluB-393, broadly inhibited IBV NA sialidase activity, protected prophylactically in vivo, and bound to the lateral corner of NA. The second group contained an active site mAb, FluB-400, that broadly inhibited IBV NA sialidase activity and virus replication in vitro in primary human respiratory epithelial cell cultures and protected against IBV in vivo when administered systemically or intranasally. Overall, the findings described here shape our mechanistic understanding of the human immune response to the IBV NA glycoprotein through the demonstration of two mAb delivery routes for protection against IBV and the identification of potential IBV therapeutic candidates.
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Anticuerpos Monoclonales , Anticuerpos Antivirales , Virus de la Influenza B , Gripe Humana , Neuraminidasa , Neuraminidasa/inmunología , Humanos , Virus de la Influenza B/inmunología , Animales , Anticuerpos Monoclonales/inmunología , Anticuerpos Antivirales/inmunología , Gripe Humana/inmunología , Gripe Humana/prevención & control , Vacunas contra la Influenza/inmunología , Ratones , Infecciones por Orthomyxoviridae/inmunología , Infecciones por Orthomyxoviridae/prevención & control , Proteínas Virales/inmunología , Replicación Viral/efectos de los fármacosRESUMEN
The backscattering of ultraviolet and visible light by a model organic (squalane) aerosol droplet (1.0
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Although average body size in the U.S. has increased in recent decades, stigma directed at individuals with higher weight has not diminished. In this study, we explored this phenomenon by investigating the relationship between people's perceived social norms regarding higher weight and their reported levels of weight bias (i.e., anti-fat attitudes). Our predictions for perceived social norms drew on the concepts of intergroup contact and ingroup favoritism, which were also probed in this study. We hypothesized that both greater descriptive norms and more favorable injunctive norms regarding higher weight would be associated with lower reported weight bias. Individuals' quantity and quality of social contact with people with higher weight were also predicted to be associated with lower weight bias. Finally, we predicted that individuals who perceived themselves as heavier would display ingroup favoritism (i.e., report less weight bias). Participants (N = 272) from the United States completed a set of online questionnaires about their perceived social norms, social contact with people with higher weight, and explicit weight bias. We found support for each of these pre-registered predictions (ps < 0.03), and post hoc analyses revealed that quality, but not quantity, of social contact with individuals with higher weight was an important predictor of lower weight bias. Together, these findings provide insight into the social psychology of weight bias and help to lay a theoretical foundation for future efforts to reduce weight stigma.
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Normas Sociales , Estigma Social , Humanos , Masculino , Femenino , Adulto , Adulto Joven , Peso Corporal , Encuestas y Cuestionarios , Persona de Mediana Edad , Adolescente , Prejuicio de Peso/psicología , Estados UnidosRESUMEN
We describe the current Good Manufacturing Practice (cGMP) production and subsequent characterization of eOD-GT8 60mer, a glycosylated self-assembling nanoparticle HIV-1 vaccine candidate and germline targeting priming immunogen. Production was carried out via transient expression in the human embryonic kidney 293 (HEK293) cell line followed by a combination of purification techniques. A large-scale cGMP (200 L) production run yielded 354 mg of the purified eOD-GT8 60mer drug product material, which was formulated at 1 mg/mL in 10% sucrose in phosphate-buffered saline (PBS) at pH 7.2. The clinical trial material was comprehensively characterized for purity, antigenicity, glycan composition, amino acid sequence, and aggregation and by several safety-related tests during cGMP lot release. A comparison of the purified products produced at the 1 L scale and 200 L cGMP scale demonstrated the consistency and robustness of the transient transfection upstream process and the downstream purification strategies. The cGMP clinical trial material was tested in a Phase 1 clinical trial (NCT03547245), is currently being stored at -80 °C, and is on a stability testing program as per regulatory guidelines. The methods described here illustrate the utility of transient transfection for cGMP production of complex products such as glycosylated self-assembling nanoparticles.
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Germinal centers (GC) are microanatomical lymphoid structures where affinity-matured memory B cells and long-lived bone marrow plasma cells are primarily generated. It is unclear how the maturation of B cells within the GC impacts the breadth and durability of B cell responses to influenza vaccination in humans. We used fine needle aspiration of draining lymph nodes to longitudinally track antigen-specific GC B cell responses to seasonal influenza vaccination. Antigen-specific GC B cells persisted for at least 13 wk after vaccination in two out of seven individuals. Monoclonal antibodies (mAbs) derived from persisting GC B cell clones exhibit enhanced binding affinity and breadth to influenza hemagglutinin (HA) antigens compared with related GC clonotypes isolated earlier in the response. Structural studies of early and late GC-derived mAbs from one clonal lineage in complex with H1 and H5 HAs revealed an altered binding footprint. Our study shows that inducing sustained GC reactions after influenza vaccination in humans supports the maturation of responding B cells.
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Linfocitos B , Centro Germinal , Vacunas contra la Influenza , Vacunación , Centro Germinal/inmunología , Humanos , Vacunas contra la Influenza/inmunología , Linfocitos B/inmunología , Glicoproteínas Hemaglutininas del Virus de la Influenza/inmunología , Gripe Humana/inmunología , Gripe Humana/prevención & control , Anticuerpos Antivirales/inmunología , Anticuerpos Monoclonales/inmunología , Adulto , Femenino , Masculino , Persona de Mediana EdadRESUMEN
Germline-targeting immunogens hold promise for initiating the induction of broadly neutralizing antibodies (bnAbs) to HIV and other pathogens. However, antibody-antigen recognition is typically dominated by heavy chain complementarity determining region 3 (HCDR3) interactions, and vaccine priming of HCDR3-dominant bnAbs by germline-targeting immunogens has not been demonstrated in humans or outbred animals. In this work, immunization with N332-GT5, an HIV envelope trimer designed to target precursors of the HCDR3-dominant bnAb BG18, primed bnAb-precursor B cells in eight of eight rhesus macaques to substantial frequencies and with diverse lineages in germinal center and memory B cells. We confirmed bnAb-mimicking, HCDR3-dominant, trimer-binding interactions with cryo-electron microscopy. Our results demonstrate proof of principle for HCDR3-dominant bnAb-precursor priming in outbred animals and suggest that N332-GT5 holds promise for the induction of similar responses in humans.
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Vacunas contra el SIDA , Anticuerpos ampliamente neutralizantes , Regiones Determinantes de Complementariedad , Centro Germinal , Anticuerpos Anti-VIH , Animales , Humanos , Vacunas contra el SIDA/inmunología , Linfocitos B/inmunología , Anticuerpos ampliamente neutralizantes/inmunología , Regiones Determinantes de Complementariedad/inmunología , Microscopía por Crioelectrón , Productos del Gen env del Virus de la Inmunodeficiencia Humana/inmunología , Centro Germinal/inmunología , Anticuerpos Anti-VIH/inmunología , Infecciones por VIH/inmunología , Infecciones por VIH/prevención & control , VIH-1/inmunología , Cadenas Pesadas de Inmunoglobulina/inmunología , Cadenas Pesadas de Inmunoglobulina/genética , Macaca mulatta , Células B de Memoria/inmunologíaRESUMEN
Influenza A virus subtype H2N2, which caused the 1957 influenza pandemic, remains a global threat. A recent phase 1 clinical trial investigating a ferritin nanoparticle vaccine displaying H2 hemagglutinin (HA) in H2-naive and H2-exposed adults enabled us to perform comprehensive structural and biochemical characterization of immune memory on the breadth and diversity of the polyclonal serum antibody response elicited. We temporally map the epitopes targeted by serum antibodies after vaccine prime and boost, revealing that previous H2 exposure results in higher responses to the variable HA head domain. In contrast, initial responses in H2-naive participants are dominated by antibodies targeting conserved epitopes. We use cryoelectron microscopy and monoclonal B cell isolation to describe the molecular details of cross-reactive antibodies targeting conserved epitopes on the HA head, including the receptor-binding site and a new site of vulnerability deemed the medial junction. Our findings accentuate the impact of pre-existing influenza exposure on serum antibody responses post-vaccination.
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Anticuerpos Antivirales , Memoria Inmunológica , Subtipo H2N2 del Virus de la Influenza A , Vacunas contra la Influenza , Vacunación , Humanos , Anticuerpos Antivirales/inmunología , Vacunas contra la Influenza/inmunología , Subtipo H2N2 del Virus de la Influenza A/inmunología , Gripe Humana/inmunología , Gripe Humana/prevención & control , Formación de Anticuerpos/inmunología , Glicoproteínas Hemaglutininas del Virus de la Influenza/inmunología , Epítopos/inmunología , Adulto , Linfocitos B/inmunologíaRESUMEN
Climate change will impact the carrot seed industry globally. One adaptation strategy to limit climatic impacts on the production of commercial carrot seeds is geographical shift. However, production must be shifted to climate-optimal places that are free from weeds such as wild carrots to avoid genetic contamination via hybridization. The process of gene flow between wild and cultivated carrots is critical to enable management of wild carrots in the face of climate change. This review systematically assesses the resilience of wild carrots to climate change and their impact on commercial carrot seed production globally with a focus on New Zealand as a major carrot seed producer. The literature was critically analyzed based on three specific components: i) resilience of wild carrots to climate change ii) genetic contamination between wild and cultivated carrots, and iii) management of wild carrots. The majority of the articles were published between 2013 and 2023 (64.71 %), and most of these studies were conducted in Europe (37.26 %) and North America (27.45 %). Country-wise analysis demonstrated that the majority of the studies were carried out in the United States (23.53 %) and the Netherlands (11.77 %). There was limited research conducted in other regions, especially in Oceania (1.96 %). Spatial distribution analysis revealed that the wild carrot was reported in around 100 countries. In New Zealand the North Island has a higher incidence of wild carrot invasion than the South Island. The findings indicated that the wild carrot is becoming more adaptable to climate change, compromising the genetic purity of cultivated carrots due to pollen flow from wild to cultivated carrots. Therefore, ongoing research will be helpful in developing sustainable weed management strategies and predicting potential geographical invasiveness. This study provides a guide for scientists, policymakers, industrialists, and farmers to control wild carrots and produce genetically pure commercial seeds amid climate change.
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Cambio Climático , Daucus carota , Flujo Génico , Daucus carota/genética , Nueva Zelanda , Polen , SemillasRESUMEN
Stabilized trimers preserving the native-like HIV envelope structure may be key components of a preventive HIV vaccine regimen to induce broadly neutralizing antibodies (bnAbs). We evaluated trimeric BG505 SOSIP.664 gp140, formulated with a novel TLR7/8 signaling adjuvant, 3M-052-AF/Alum, for safety, adjuvant dose-finding and immunogenicity in a first-in-healthy adult (n=17), randomized, placebo-controlled trial (HVTN 137A). The vaccine regimen appeared safe. Robust, trimer-specific antibody, B-cell and CD4+ T-cell responses emerged post-vaccination. Five vaccinees developed serum autologous tier-2 nAbs (ID50 titer, 1:28-1:8647) after 2-3 doses targeting C3/V5 and/or V1/V2/V3 Env regions by electron microscopy and mutated pseudovirus-based neutralization analyses. Trimer-specific, B-cell-derived monoclonal antibody activities confirmed these results and showed weak heterologous neutralization in the strongest responder. Our findings demonstrate the clinical utility of the 3M-052-AF/alum adjuvant and support further improvements of trimer-based Env immunogens to focus responses on multiple broad nAb epitopes. KEY TAKEAWAY/TAKE-HOME MESSAGES: HIV BG505 SOSIP.664 trimer with novel 3M-052-AF/alum adjuvant in humans appears safe and induces serum neutralizing antibodies to matched clade A, tier 2 virus, that map to diverse Env epitopes with relatively high titers. The novel adjuvant may be an important mediator of vaccine response.
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Germline-targeting (GT) HIV vaccine strategies are predicated on deriving broadly neutralizing antibodies (bnAbs) through multiple boost immunogens. However, as the recruitment of memory B cells (MBCs) to germinal centers (GCs) is inefficient and may be derailed by serum antibody-induced epitope masking, driving further B cell receptor (BCR) modification in GC-experienced B cells after boosting poses a challenge. Using humanized immunoglobulin knockin mice, we found that GT protein trimer immunogen N332-GT5 could prime inferred-germline precursors to the V3-glycan-targeted bnAb BG18 and that B cells primed by N332-GT5 were effectively boosted by either of two novel protein immunogens designed to have minimum cross-reactivity with the off-target V1-binding responses. The delivery of the prime and boost immunogens as messenger RNA lipid nanoparticles (mRNA-LNPs) generated long-lasting GCs, somatic hypermutation, and affinity maturation and may be an effective tool in HIV vaccine development.
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Vacunas contra el SIDA , Anticuerpos ampliamente neutralizantes , Centro Germinal , Anticuerpos Anti-VIH , VIH-1 , Inmunización Secundaria , Nanopartículas , Vacunas de ARNm , Animales , Humanos , Ratones , Vacunas contra el SIDA/inmunología , Linfocitos B/inmunología , Anticuerpos ampliamente neutralizantes/inmunología , Reacciones Cruzadas , Técnicas de Sustitución del Gen , Centro Germinal/inmunología , Anticuerpos Anti-VIH/inmunología , Proteína gp120 de Envoltorio del VIH/inmunología , Proteína gp120 de Envoltorio del VIH/química , Proteína gp120 de Envoltorio del VIH/genética , Infecciones por VIH/inmunología , Infecciones por VIH/prevención & control , VIH-1/inmunología , VIH-1/genética , Liposomas , Células B de Memoria/inmunología , Receptores de Antígenos de Linfocitos B/inmunología , Receptores de Antígenos de Linfocitos B/genética , Hipermutación Somática de Inmunoglobulina , Vacunas de ARNm/inmunología , Femenino , Ratones Endogámicos C57BLRESUMEN
BACKGROUND: Optimal size at birth dictates perinatal survival and long-term risk of developing common disorders such as obesity, type 2 diabetes and cardiovascular disease. The imprinted Grb10 gene encodes a signalling adaptor protein capable of inhibiting receptor tyrosine kinases, including the insulin receptor (Insr) and insulin-like growth factor type 1 receptor (Igf1r). Grb10 restricts fetal growth such that Grb10 knockout (KO) mice are at birth some 25-35% larger than wild type. Using a mouse genetic approach, we test the widely held assumption that Grb10 influences growth through interaction with Igf1r, which has a highly conserved growth promoting role. RESULTS: Should Grb10 interact with Igf1r to regulate growth Grb10:Igf1r double mutant mice should be indistinguishable from Igf1r KO single mutants, which are around half normal size at birth. Instead, Grb10:Igf1r double mutants were intermediate in size between Grb10 KO and Igf1r KO single mutants, indicating additive effects of the two signalling proteins having opposite actions in separate pathways. Some organs examined followed a similar pattern, though Grb10 KO neonates exhibited sparing of the brain and kidneys, whereas the influence of Igf1r extended to all organs. An interaction between Grb10 and Insr was similarly investigated. While there was no general evidence for a major interaction for fetal growth regulation, the liver was an exception. The liver in Grb10 KO mutants was disproportionately overgrown with evidence of excess lipid storage in hepatocytes, whereas Grb10:Insr double mutants were indistinguishable from Insr single mutants or wild types. CONCLUSIONS: Grb10 acts largely independently of Igf1r or Insr to control fetal growth and has a more variable influence on individual organs. Only the disproportionate overgrowth and excess lipid storage seen in the Grb10 KO neonatal liver can be explained through an interaction between Grb10 and the Insr. Our findings are important for understanding how positive and negative influences on fetal growth dictate size and tissue proportions at birth.
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Desarrollo Fetal , Proteína Adaptadora GRB10 , Ratones Noqueados , Receptor IGF Tipo 1 , Receptor de Insulina , Animales , Proteína Adaptadora GRB10/genética , Proteína Adaptadora GRB10/metabolismo , Receptor IGF Tipo 1/genética , Receptor IGF Tipo 1/metabolismo , Ratones , Receptor de Insulina/genética , Receptor de Insulina/metabolismo , Desarrollo Fetal/genética , Impresión Genómica , Femenino , Masculino , Péptidos Similares a la InsulinaRESUMEN
Enterotoxigenic Escherichia coli (ETEC) cause hundreds of millions of cases of infectious diarrhea annually, predominantly in children from low-middle income regions. Notably, in children, as well as human volunteers challenged with ETEC, diarrheal severity is significantly increased severity in blood group A (bgA) individuals. EtpA, is a secreted glycoprotein adhesin that functions as a blood group A lectin to promote critical interactions between ETEC and blood group A glycans on intestinal epithelia for effective bacterial adhesion and toxin delivery. EtpA is highly immunogenic resulting in robust antibody responses following natural infection and experimental challenge of human volunteers with ETEC. To understand how EtpA directs ETEC-blood group A interactions and stimulates adaptive immunity, we mutated EtpA, mapped its glycosylation by mass-spectrometry (MS), isolated polyclonal (pAbs) and monoclonal antibodies (mAbs) from vaccinated mice and ETEC-infected human volunteers, and determined structures of antibody-EtpA complexes by cryo-electron microscopy. Both bgA and mAbs that inhibited EtpA-bgA interactions and ETEC adhesion, bound to the C-terminal repeat domain highlighting this region as crucial for ETEC pathogen-host interaction. MS analysis uncovered extensive and heterogeneous N-linked glycosylation of EtpA and cryo-EM structures revealed that mAbs directly engage these unique glycan containing epitopes. Finally, electron microscopy-based polyclonal epitope mapping revealed antibodies targeting numerous distinct epitopes on N and C-terminal domains, suggesting that EtpA vaccination generates responses against neutralizing and decoy regions of the molecule. Collectively, we anticipate that these data will inform our general understanding of pathogen-host glycan interactions and adaptive immunity relevant to rational vaccine subunit design.
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Broadly neutralizing antibodies (bnAbs) targeting the hemagglutinin (HA) stem of influenza A viruses (IAVs) tend to be effective against either group 1 or group 2 viral diversity. In rarer cases, intergroup protective bnAbs can be generated by human antibody paratopes that accommodate the conserved glycan differences between the group 1 and group 2 stems. We applied germline-engaging nanoparticle immunogens to elicit a class of cross-group bnAbs from physiological precursor frequency within a humanized mouse model. Cross-group protection depended on the presence of the human bnAb precursors within the B cell repertoire, and the vaccine-expanded antibodies enriched for an N55T substitution in the CDRH2 loop, a hallmark of the bnAb class. Structurally, this single mutation introduced a flexible fulcrum to accommodate glycosylation differences and could alone enable cross-group protection. Thus, broad IAV immunity can be expanded from the germline repertoire via minimal antigenic input and an exceptionally simple antibody development pathway.
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Anticuerpos Neutralizantes , Anticuerpos Antivirales , Virus de la Influenza A , Vacunas contra la Influenza , Infecciones por Orthomyxoviridae , Vacunación , Animales , Ratones , Humanos , Anticuerpos Antivirales/inmunología , Vacunas contra la Influenza/inmunología , Virus de la Influenza A/inmunología , Anticuerpos Neutralizantes/inmunología , Infecciones por Orthomyxoviridae/inmunología , Infecciones por Orthomyxoviridae/prevención & control , Glicoproteínas Hemaglutininas del Virus de la Influenza/inmunología , Sustitución de Aminoácidos , Linfocitos B/inmunología , Gripe Humana/inmunología , Gripe Humana/prevención & control , Anticuerpos ampliamente neutralizantes/inmunologíaRESUMEN
Vaccination strategies against HIV-1 aim to elicit broadly neutralizing antibodies (bnAbs) using prime-boost regimens with HIV envelope (Env) immunogens. Early antibody responses to easily accessible epitopes on these antigens are directed to non-neutralizing epitopes instead of bnAb epitopes. Autologous neutralizing antibody responses appear upon boosting once immunodominant epitopes are saturated. Here we report another type of antibody response that arises after repeated immunizations with HIV Env immunogens and present the structures of six anti-immune complexes discovered using polyclonal epitope mapping. The anti-immune complex antibodies target idiotopes composed of framework regions of antibodies bound to Env. This work sheds light on current vaccine development efforts for HIV, as well as for other pathogens, in which repeated exposure to antigen is required.
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Recombinant native-like HIV-1 envelope glycoprotein (Env) trimers are used in candidate vaccines aimed at inducing broadly neutralizing antibodies. While state-of-the-art SOSIP or single-chain Env designs can be expressed as native-like trimers, undesired monomers, dimers and malformed trimers that elicit non-neutralizing antibodies are also formed, implying that these designs could benefit from further modifications for gene-based vaccination approaches. Here, we describe the triple tandem trimer (TTT) design, in which three Env protomers are genetically linked in a single open reading frame and express as native-like trimers. Viral vectored Env TTT induced similar neutralization titers but with a higher proportion of trimer-specific responses. The TTT design was also applied to generate influenza hemagglutinin (HA) trimers without the need for trimerization domains. Additionally, we used TTT to generate well-folded chimeric Env and HA trimers that harbor protomers from three different strains. In summary, the TTT design is a useful platform for the design of HIV-1 Env and influenza HA immunogens for a multitude of vaccination strategies.