RESUMO
Current prophylactic human immunodeficiency virus 1 (HIV-1) vaccine research aims to elicit broadly neutralizing antibodies (bnAbs). Membrane-proximal external region (MPER)-targeting bnAbs, such as 10E8, provide exceptionally broad neutralization, but some are autoreactive. Here, we generated humanized B cell antigen receptor knock-in mouse models to test whether a series of germline-targeting immunogens could drive MPER-specific precursors toward bnAbs. We found that recruitment of 10E8 precursors to germinal centers (GCs) required a minimum affinity for germline-targeting immunogens, but the GC residency of MPER precursors was brief due to displacement by higher-affinity endogenous B cell competitors. Higher-affinity germline-targeting immunogens extended the GC residency of MPER precursors, but robust long-term GC residency and maturation were only observed for MPER-HuGL18, an MPER precursor clonotype able to close the affinity gap with endogenous B cell competitors in the GC. Thus, germline-targeting immunogens could induce MPER-targeting antibodies, and B cell residency in the GC may be regulated by a precursor-competitor affinity gap.
Assuntos
Afinidade de Anticorpos , Linfócitos B , Centro Germinativo , Anticorpos Anti-HIV , HIV-1 , Centro Germinativo/imunologia , Animais , Camundongos , Humanos , Linfócitos B/imunologia , HIV-1/imunologia , Anticorpos Anti-HIV/imunologia , Afinidade de Anticorpos/imunologia , Anticorpos Neutralizantes/imunologia , Infecções por HIV/imunologia , Vacinas contra a AIDS/imunologia , Receptores de Antígenos de Linfócitos B/metabolismo , Receptores de Antígenos de Linfócitos B/imunologia , Técnicas de Introdução de Genes , Camundongos Transgênicos , Anticorpos Amplamente Neutralizantes/imunologia , Camundongos Endogâmicos C57BLRESUMO
A key barrier to the development of vaccines that induce broadly neutralizing antibodies (bnAbs) against human immunodeficiency virus (HIV) and other viruses of high antigenic diversity is the design of priming immunogens that induce rare bnAb-precursor B cells. The high neutralization breadth of the HIV bnAb 10E8 makes elicitation of 10E8-class bnAbs desirable; however, the recessed epitope within gp41 makes envelope trimers poor priming immunogens and requires that 10E8-class bnAbs possess a long heavy chain complementarity determining region 3 (HCDR3) with a specific binding motif. We developed germline-targeting epitope scaffolds with affinity for 10E8-class precursors and engineered nanoparticles for multivalent display. Scaffolds exhibited epitope structural mimicry and bound bnAb-precursor human naive B cells in ex vivo screens, protein nanoparticles induced bnAb-precursor responses in stringent mouse models and rhesus macaques, and mRNA-encoded nanoparticles triggered similar responses in mice. Thus, germline-targeting epitope scaffold nanoparticles can elicit rare bnAb-precursor B cells with predefined binding specificities and HCDR3 features.
Assuntos
Vacinas contra a AIDS , Anticorpos Neutralizantes , Anticorpos Anti-HIV , Proteína gp41 do Envelope de HIV , Infecções por HIV , HIV-1 , Macaca mulatta , Animais , Humanos , Proteína gp41 do Envelope de HIV/imunologia , Anticorpos Anti-HIV/imunologia , Camundongos , Vacinas contra a AIDS/imunologia , Anticorpos Neutralizantes/imunologia , HIV-1/imunologia , Infecções por HIV/imunologia , Infecções por HIV/prevenção & controle , Infecções por HIV/virologia , Vacinação , Anticorpos Amplamente Neutralizantes/imunologia , Linfócitos B/imunologia , Nanopartículas/química , Feminino , Regiões Determinantes de Complementaridade/imunologia , Epitopos/imunologiaRESUMO
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.
Assuntos
Anticorpos Neutralizantes , Anticorpos Antivirais , Vírus da Influenza A , Vacinas contra Influenza , Infecções por Orthomyxoviridae , Vacinação , Animais , Camundongos , Humanos , Anticorpos Antivirais/imunologia , Vacinas contra Influenza/imunologia , Vírus da Influenza A/imunologia , Anticorpos Neutralizantes/imunologia , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Substituição de Aminoácidos , Linfócitos B/imunologia , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Anticorpos Amplamente Neutralizantes/imunologiaRESUMO
Antibodies are produced at high rates to provide immunoprotection, which puts pressure on the B cell translational machinery. Here, we identified a pattern of codon usage conserved across antibody genes. One feature thereof is the hyperutilization of codons that lack genome-encoded Watson-Crick transfer RNAs (tRNAs), instead relying on the posttranscriptional tRNA modification inosine (I34), which expands the decoding capacity of specific tRNAs through wobbling. Antibody-secreting cells had increased I34 levels and were more reliant on I34 for protein production than naïve B cells. Furthermore, antibody I34-dependent codon usage may influence B cell passage through regulatory checkpoints. Our work elucidates the interface between the tRNA pool and protein production in the immune system and has implications for the design and selection of antibodies for vaccines and therapeutics.
Assuntos
Anticorpos , Formação de Anticorpos , Linfócitos B , Uso do Códon , Cadeias Pesadas de Imunoglobulinas , Inosina , RNA de Transferência , Formação de Anticorpos/genética , Códon/genética , Inosina/genética , Inosina/metabolismo , RNA de Transferência/genética , Anticorpos/genética , Humanos , Linfócitos B/imunologia , Cadeias Pesadas de Imunoglobulinas/genéticaRESUMO
Germline-targeting (GT) protein immunogens to induce VRC01-class broadly neutralizing antibodies (bnAbs) to the CD4-binding site of the HIV envelope (Env) have shown promise in clinical trials. Here, we preclinically validated a lipid nanoparticle-encapsulated nucleoside mRNA (mRNA-LNP) encoding eOD-GT8 60mer as a soluble self-assembling nanoparticle in mouse models. In a model with three humanized B cell lineages bearing distinct VRC01-precursor B cell receptors (BCRs) with similar affinities for eOD-GT8, all lineages could be simultaneously primed and undergo diversification and affinity maturation without exclusionary competition. Boosts drove precursor B cell participation in germinal centers; the accumulation of somatic hypermutations, including in key VRC01-class positions; and affinity maturation to boost and native-like antigens in two of the three precursor lineages. We have preclinically validated a prime-boost regimen of soluble self-assembling nanoparticles encoded by mRNA-LNP, demonstrating that multiple lineages can be primed, boosted, and diversified along the bnAb pathway.
Assuntos
Anticorpos Amplamente Neutralizantes , Nanopartículas , RNA Mensageiro , Animais , Camundongos , Humanos , RNA Mensageiro/imunologia , RNA Mensageiro/genética , Nanopartículas/química , Anticorpos Amplamente Neutralizantes/imunologia , Anticorpos Anti-HIV/imunologia , Lipídeos/imunologia , Infecções por HIV/imunologia , Vacinas contra a AIDS/imunologia , Anticorpos Neutralizantes/imunologia , HIV-1/imunologia , Feminino , Anticorpos Monoclonais , LipossomosRESUMO
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.