RESUMO
The VH6-1 class of antibodies includes some of the broadest and most potent antibodies that neutralize influenza A virus. Here, we elicit and isolate anti-idiotype antibodies against germline versions of VH6-1 antibodies, use these to sort human leukocytes, and isolate a new VH6-1-class member, antibody L5A7, which potently neutralized diverse group 1 and group 2 influenza A strains. While its heavy chain derived from the canonical IGHV6-1 heavy chain gene used by the class, L5A7 utilized a light chain gene, IGKV1-9, which had not been previously observed in other VH6-1-class antibodies. The cryo-EM structure of L5A7 in complex with Indonesia 2005 hemagglutinin revealed a nearly identical binding mode to other VH6-1-class members. The structure of L5A7 bound to the isolating anti-idiotype antibody, 28H6E11, revealed a shared surface for binding anti-idiotype and hemagglutinin that included two critical L5A7 regions: an FG motif in the third heavy chain-complementary determining region (CDR H3) and the CDR L1 loop. Surprisingly, the chemistries of L5A7 interactions with hemagglutinin and with anti-idiotype were substantially different. Overall, we demonstrate anti-idiotype-based isolation of a broad and potent influenza A virus-neutralizing antibody, revealing that anti-idiotypic selection of antibodies can involve features other than chemical mimicry of the target antigen.
Assuntos
Anticorpos Anti-Idiotípicos , Anticorpos Neutralizantes , Anticorpos Antivirais , Glicoproteínas de Hemaglutininação de Vírus da Influenza , Vírus da Influenza A , Humanos , Vírus da Influenza A/imunologia , Anticorpos Antivirais/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/isolamento & purificação , Anticorpos Anti-Idiotípicos/imunologia , Anticorpos Anti-Idiotípicos/isolamento & purificação , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Influenza Humana/imunologia , Influenza Humana/virologia , Animais , Cadeias Pesadas de Imunoglobulinas/imunologia , Cadeias Pesadas de Imunoglobulinas/químicaRESUMO
BACKGROUND: Broadly neutralizing antibodies (bnAbs) are a promising approach for HIV-1 prevention. In the Antibody Mediated Prevention (AMP) trials, a CD4-binding site targeting bnAb, VRC01, administered intravenously (IV), demonstrated 75% prevention efficacy against highly neutralization-sensitive viruses but was ineffective against less sensitive viruses. VRC07-523LS is a next-generation bnAb targeting the CD4-binding site and was engineered for increased neutralization breadth and half-life. We conducted a multicenter, randomized, partially blinded Phase I clinical trial to evaluate the safety and serum concentrations of VRC07-523LS, administered in multiple doses and routes to healthy adults without HIV. METHODS AND FINDINGS: Participants were recruited between 2 February 2018 and 9 October 2018. A total of 124 participants were randomized to receive 5 VRC07-523LS administrations via IV (T1: 2.5 mg/kg, T2: 5 mg/kg, T3: 20 mg/kg), subcutaneous (SC) (T4: 2.5 mg/kg, T5: 5 mg/kg), or intramuscular (IM) (T6: 2.5 mg/kg or P6: placebo) routes at 4-month intervals. Participants and site staff were blinded to VRC07-523LS versus placebo for the IM group, while all other doses and routes were open-label. Safety data were collected for 144 weeks following the first administration. VRC07-523LS serum concentrations were measured by ELISA through Day 112 in all participants and by binding antibody multiplex assay (BAMA) thereafter in 60 participants (10 per treatment group) through Day 784. Compartmental population pharmacokinetic (PK) analyses were conducted to evaluate the VRC07-523LS serum PK. Neutralization activity was measured in a TZM-bl assay and antidrug antibodies (ADAs) were assayed using a tiered bridging assay testing strategy. Injections and infusions were well tolerated, with mild pain or tenderness reported commonly in the SC and IM groups, and mild to moderate erythema or induration reported commonly in the SC groups. Infusion reactions were reported in 3 of 20 participants in the 20 mg/kg IV group. Peak geometric mean (GM) concentrations (95% confidence intervals [95% CIs]) following the first administration were 29.0 µg/mL (25.2, 33.4), 58.5 µg/mL (49.4, 69.3), and 257.2 µg/mL (127.5, 518.9) in T1-T3 with IV dosing; 10.8 µg/mL (8.8, 13.3) and 22.8 µg/mL (20.1, 25.9) in T4-T5 with SC dosing; and 16.4 µg/mL (14.7, 18.2) in T6 with IM dosing. Trough GM (95% CIs) concentrations immediately prior to the second administration were 3.4 µg/mL (2.5, 4.6), 6.5 µg/mL (5.6, 7.5), and 27.2 µg/mL (23.9, 31.0) with IV dosing; 0.97 µg/mL (0.65, 1.4) and 3.1 µg/mL (2.2, 4.3) with SC dosing, and 2.6 µg/mL (2.05, 3.31) with IM dosing. Peak VRC07-523LS serum concentrations increased linearly with the administered dose. At a given dose, peak and trough concentrations, as well as serum neutralization titers, were highest in the IV groups, reflecting the lower bioavailability following SC and IM administration. A single participant was found to have low titer ADA at a lone time point. VRC07-523LS has an estimated mean half-life of 42 days across all doses and routes (95% CI: 40.5, 43.5), over twice as long as VRC01 (15 days). CONCLUSIONS: VRC07-523LS was safe and well tolerated across a range of doses and routes and is a promising long-acting bnAb for inclusion in HIV-1 prevention regimens. TRIAL REGISTRATION: ClinicalTrials.gov/ NCT03387150 (posted on 21 December 2017).
Assuntos
Anticorpos Neutralizantes , Anticorpos Anti-HIV , Humanos , Masculino , Feminino , Adulto , Anticorpos Neutralizantes/sangue , Anticorpos Anti-HIV/sangue , Pessoa de Meia-Idade , Infecções por HIV/tratamento farmacológico , Infecções por HIV/imunologia , HIV-1/imunologia , Adulto Jovem , Anticorpos Amplamente Neutralizantes/administração & dosagem , Anticorpos Amplamente Neutralizantes/efeitos adversos , Adolescente , Injeções IntramuscularesRESUMO
BACKGROUND: A self-assembling SARS-CoV-2 WA-1 recombinant spike ferritin nanoparticle (SpFN) vaccine co-formulated with Army Liposomal Formulation (ALFQ) adjuvant containing monophosphoryl lipid A and QS-21 (SpFN/ALFQ) has shown protective efficacy in animal challenge models. This trial aims to assess the safety and immunogenicity of SpFN/ALFQ in a first-in-human clinical trial. METHODS: In this phase 1, randomised, double-blind, placebo-controlled, first-in-human clinical trial, adults were randomly assigned (5:5:2) to receive 25 µg or 50 µg of SpFN/ALFQ or saline placebo intramuscularly at day 1 and day 29, with an optional open-label third vaccination at day 181. Enrolment and randomisation occurred sequentially by group; randomisation was done by an interactive web-based randomisation system and only designated unmasked study personnel had access to the randomisation code. Adults were required to be seronegative and unvaccinated for inclusion. Local and systemic reactogenicity, adverse events, binding and neutralising antibodies, and antigen-specific T-cell responses were quantified. For safety analyses, exact 95% Clopper-Pearson CIs for the probability of any incidence of an unsolicited adverse event was computed for each group. For immunogenicity results, CIs for binary variables were computed using the exact Clopper-Pearson methodology, while CIs for geometric mean titres were based on 10 000 empirical bootstrap samples. Post-hoc, paired one-sample t tests were used to assess the increase in mean log-10 neutralising antibody titres between day 29 and day 43 (after the second vaccination) for the primary SARS-CoV-2 targets of interest. This trial is registered at ClinicalTrials.gov, NCT04784767, and is closed to new participants. FINDINGS: Between April 7, and June 29, 2021, 29 participants were enrolled in the study. 20 individuals were assigned to receive 25 µg SpFN/ALFQ, four to 50 µg SpFN/ALFQ, and five to placebo. Neutralising antibody responses peaked at day 43, 2 weeks after the second dose. Neutralisation activity against multiple omicron subvariants decayed more slowly than against the D614G or beta variants until 5 months after second vaccination for both dose groups. CD4+ T-cell responses were elicited 4 weeks after the first dose and were boosted after a second dose of SpFN/ALFQ for both dose groups. Neutralising antibody titres against early omicron subvariants and clade 1 sarbecoviruses were detectable after two immunisations and peaked after the third immunisation for both dose groups. Neutralising antibody titres against XBB.1.5 were detected after three vaccinations. Passive IgG transfer from vaccinated volunteers into Syrian golden hamsters controlled replication of SARS-CoV-1 after challenge. INTERPRETATION: SpFN/ALFQ was well tolerated and elicited robust and durable binding antibody and neutralising antibody titres against a broad panel of SARS-CoV-2 variants and other sarbecoviruses. FUNDING: US Department of Defense, Defense Health Agency.
Assuntos
Vacinas contra COVID-19 , COVID-19 , Ferritinas , Lipídeo A , Lipossomos , Nanopartículas , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Humanos , Vacinas contra COVID-19/imunologia , Vacinas contra COVID-19/administração & dosagem , Vacinas contra COVID-19/efeitos adversos , Método Duplo-Cego , Adulto , Masculino , Feminino , COVID-19/prevenção & controle , COVID-19/imunologia , SARS-CoV-2/imunologia , Nanopartículas/administração & dosagem , Lipídeo A/análogos & derivados , Lipídeo A/administração & dosagem , Lipídeo A/farmacologia , Lipídeo A/imunologia , Lipossomos/administração & dosagem , Glicoproteína da Espícula de Coronavírus/imunologia , Saponinas/administração & dosagem , Saponinas/imunologia , Saponinas/farmacologia , Saponinas/efeitos adversos , Anticorpos Antivirais/sangue , Pessoa de Meia-Idade , Adjuvantes Imunológicos/administração & dosagem , Adjuvantes Imunológicos/farmacologia , Adjuvantes de Vacinas/administração & dosagem , Anticorpos Neutralizantes/sangue , Adulto Jovem , NanovacinasRESUMO
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.
Assuntos
Anticorpos Antivirais , Memória Imunológica , Vírus da Influenza A Subtipo H2N2 , Vacinas contra Influenza , Vacinação , Humanos , Anticorpos Antivirais/imunologia , Vacinas contra Influenza/imunologia , Vírus da Influenza A Subtipo H2N2/imunologia , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Formação de Anticorpos/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Epitopos/imunologia , Adulto , Linfócitos B/imunologiaRESUMO
BACKGROUNDBroadly neutralizing monoclonal antibodies (bNAbs) represent a promising strategy for HIV-1 immunoprophylaxis and treatment. 10E8VLS and VRC07-523LS are bNAbs that target the highly conserved membrane-proximal external region (MPER) and the CD4-binding site of the HIV-1 viral envelope glycoprotein, respectively.METHODSIn this phase 1, open-label trial, we evaluated the safety and pharmacokinetics of 5 mg/kg 10E8VLS administered alone, or concurrently with 5 mg/kg VRC07-523LS, via s.c. injection to healthy non-HIV-infected individuals.RESULTSEight participants received either 10E8VLS alone (n = 6) or 10E8VLS and VRC07-523LS in combination (n = 2). Five (n = 5 of 8, 62.5%) participants who received 10E8VLS experienced moderate local reactogenicity, and 1 participant (n = 1/8, 12.5%) experienced severe local reactogenicity. Further trial enrollment was stopped, and no participant received repeat dosing. All local reactogenicity resolved without sequelae. 10E8VLS retained its neutralizing capacity, and no functional anti-drug antibodies were detected; however, a serum t1/2 of 8.1 days was shorter than expected. Therefore, the trial was voluntarily stopped per sponsor decision (Vaccine Research Center, National Institute of Allergy and Infectious Diseases [NIAID], NIH). Mechanistic studies performed to investigate the underlying reason for the reactogenicity suggest that multiple mechanisms may have contributed, including antibody aggregation and upregulation of local inflammatory markers.CONCLUSION10E8VLS resulted in unexpected reactogenicity and a shorter t1/2 in comparison with previously tested bNAbs. These studies may facilitate identification of nonreactogenic second-generation MPER-targeting bNAbs, which could be an effective strategy for HIV-1 immunoprophylaxis and treatment.TRIAL REGISTRATIONClinicaltrials.gov, accession no. NCT03565315.FUNDINGDivision of Intramural Research, National Institute of Allergy and Infectious Diseases, NIH.
Assuntos
Infecções por HIV , Soropositividade para HIV , HIV-1 , Humanos , Infecções por HIV/tratamento farmacológico , Infecções por HIV/prevenção & controle , Anticorpos Anti-HIV , Anticorpos Amplamente Neutralizantes/farmacologia , Anticorpos Monoclonais/farmacologiaRESUMO
BACKGROUND: Subcutaneous administration of the monoclonal antibody L9LS protected adults against controlled Plasmodium falciparum infection in a phase 1 trial. Whether a monoclonal antibody administered subcutaneously can protect children from P. falciparum infection in a region where this organism is endemic is unclear. METHODS: We conducted a phase 2 trial in Mali to assess the safety and efficacy of subcutaneous administration of L9LS in children 6 to 10 years of age over a 6-month malaria season. In part A of the trial, safety was assessed at three dose levels in adults, followed by assessment at two dose levels in children. In part B of the trial, children were randomly assigned, in a 1:1:1 ratio, to receive 150 mg of L9LS, 300 mg of L9LS, or placebo. The primary efficacy end point, assessed in a time-to-event analysis, was the first P. falciparum infection, as detected on blood smear performed at least every 2 weeks for 24 weeks. A secondary efficacy end point was the first episode of clinical malaria, as assessed in a time-to-event analysis. RESULTS: No safety concerns were identified in the dose-escalation part of the trial (part A). In part B, 225 children underwent randomization, with 75 children assigned to each group. No safety concerns were identified in part B. P. falciparum infection occurred in 36 participants (48%) in the 150-mg group, in 30 (40%) in the 300-mg group, and in 61 (81%) in the placebo group. The efficacy of L9LS against P. falciparum infection, as compared with placebo, was 66% (adjusted confidence interval [95% CI], 45 to 79) with the 150-mg dose and 70% (adjusted 95% CI, 50 to 82) with the 300-mg dose (P<0.001 for both comparisons). Efficacy against clinical malaria was 67% (adjusted 95% CI, 39 to 82) with the 150-mg dose and 77% (adjusted 95% CI, 55 to 89) with the 300-mg dose (P<0.001 for both comparisons). CONCLUSIONS: Subcutaneous administration of L9LS to children was protective against P. falciparum infection and clinical malaria over a period of 6 months. (Funded by the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT05304611.).
Assuntos
Anticorpos Monoclonais Humanizados , Malária Falciparum , Adulto , Criança , Feminino , Humanos , Masculino , Relação Dose-Resposta a Droga , Método Duplo-Cego , Doenças Endêmicas/prevenção & controle , Injeções Subcutâneas , Estimativa de Kaplan-Meier , Malária Falciparum/tratamento farmacológico , Malária Falciparum/epidemiologia , Malária Falciparum/prevenção & controle , Mali/epidemiologia , Plasmodium falciparum , Resultado do Tratamento , Anticorpos Monoclonais Humanizados/administração & dosagem , Anticorpos Monoclonais Humanizados/efeitos adversos , Anticorpos Monoclonais Humanizados/uso terapêutico , Terapia Diretamente Observada , Combinação Arteméter e Lumefantrina/administração & dosagem , Combinação Arteméter e Lumefantrina/uso terapêutico , Adulto Jovem , Pessoa de Meia-IdadeRESUMO
Continuously evolving influenza viruses cause seasonal epidemics and pose global pandemic threats. Although viral neuraminidase (NA) is an effective drug and vaccine target, our understanding of the NA antigenic landscape still remains incomplete. Here, we describe NA-specific human antibodies that target the underside of the NA globular head domain, inhibit viral propagation of a wide range of human H3N2, swine-origin variant H3N2, and H2N2 viruses, and confer both pre- and post-exposure protection against lethal H3N2 infection in mice. Cryo-EM structures of two such antibodies in complex with NA reveal non-overlapping epitopes covering the underside of the NA head. These sites are highly conserved among N2 NAs yet inaccessible unless the NA head tilts or dissociates. Our findings help guide the development of effective countermeasures against ever-changing influenza viruses by identifying hidden conserved sites of vulnerability on the NA underside.
Assuntos
Vacinas contra Influenza , Influenza Humana , Infecções por Orthomyxoviridae , Humanos , Animais , Camundongos , Suínos , Proteínas Virais/genética , Neuraminidase , Vírus da Influenza A Subtipo H3N2 , Anticorpos Monoclonais , Anticorpos AntiviraisRESUMO
Antigenic drift, the gradual accumulation of amino acid substitutions in the influenza virus hemagglutinin (HA) receptor protein, enables viral immune evasion. Antibodies (Abs) specific for the drift-resistant HA stem region are a promising universal influenza vaccine target. Although anti-stem Abs are not believed to block viral attachment, here we show that complement component 1q (C1q), a 460-kilodalton protein with six Ab Fc-binding domains, confers attachment inhibition to anti-stem Abs and enhances their fusion and neuraminidase inhibition. As a result, virus neutralization activity in vitro is boosted up to 30-fold, and in vivo protection from influenza PR8 infection in mice is enhanced. These effects reflect increased steric hindrance and not increased Ab avidity. C1q greatly expands the anti-stem Ab viral escape repertoire to include residues throughout the HA, some of which cause antigenic alterations in the globular region or modulate HA receptor avidity. We also show that C1q enhances the neutralization activity of non-receptor binding domain anti-SARS-CoV-2 spike Abs, an effect dependent on spike density on the virion surface. These findings demonstrate that C1q can greatly expand Ab function and thereby contribute to viral evolution and immune escape.
Assuntos
Vacinas contra Influenza , Influenza Humana , Camundongos , Animais , Humanos , Hemaglutininas , Complemento C1q , Ligação Viral , Glicoproteínas de Hemaglutininação de Vírus da Influenza , Anticorpos AntiviraisRESUMO
Vaccine priming immunogens that activate germline precursors for broadly neutralizing antibodies (bnAbs) have promise for development of precision vaccines against major human pathogens. In a clinical trial of the eOD-GT8 60mer germline-targeting immunogen, higher frequencies of vaccine-induced VRC01-class bnAb-precursor B cells were observed in the high dose compared to the low dose group. Through immunoglobulin heavy chain variable (IGHV) genotyping, statistical modeling, quantification of IGHV1-2 allele usage and B cell frequencies in the naive repertoire for each trial participant, and antibody affinity analyses, we found that the difference between dose groups in VRC01-class response frequency was best explained by IGHV1-2 genotype rather than dose and was most likely due to differences in IGHV1-2 B cell frequencies for different genotypes. The results demonstrate the need to define population-level immunoglobulin allelic variations when designing germline-targeting immunogens and evaluating them in clinical trials.
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Soluble 'SOSIP'-stabilized HIV-1 envelope glycoprotein (Env) trimers elicit dominant antibody responses targeting their glycan-free base regions, potentially diminishing neutralizing responses. Previously, using a nonhuman primate model, we demonstrated that priming with fusion peptide (FP)-carrier conjugate immunogens followed by boosting with Env trimers reduced the anti-base response. Further, we demonstrated that longer immunization intervals further reduced anti-base responses and increased neutralization breadth. Here, we demonstrate that long trimer-boosting intervals, but not long FP immunization intervals, reduce the anti-base response. Additionally, we identify that FP priming before trimer immunization enhances antibody avidity to the Env trimer. We also establish that adjuvants Matrix M and Adjuplex further reduce anti-base responses and increase neutralizing titers. FP priming, long trimer-immunization interval, and an appropriate adjuvant can thus reduce anti-base antibody responses and improve Env-directed vaccine outcomes.
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Background: Broadly neutralizing antibodies (bnAbs) are a promising approach for HIV-1 prevention. In the only bnAb HIV prevention efficacy studies to date, the Antibody Mediated Prevention (AMP) trials, a CD4-binding site targeting bnAb, VRC01, administered intravenously (IV), demonstrated 75% prevention efficacy against highly neutralization-sensitive viruses but was ineffective against less sensitive viruses. Greater efficacy is required before passively administered bnAbs become a viable option for HIV prevention; furthermore subcutaneous (SC) or intramuscular (IM) administration may be preferred. VRC07-523LS is a next-generation bnAb targeting the CD4-binding site and was engineered for increased neutralization breadth and half-life. Methods: Participants were recruited between 02 February 2018 and 09 October 2018. 124 healthy participants without HIV were randomized to receive five VRC07-523LS administrations via IV (T1: 2.5 mg/kg, T2: 5 mg/kg, T3: 20 mg/kg), SC (T4: 2.5 mg/kg, T5: 5 mg/kg) or IM (T6: 2.5 mg/kg or P6: placebo) routes at four-month intervals. Safety data were collected for 144 weeks following the first administration. VRC07-523LS serum concentrations were measured by ELISA after the first dose through Day 112 in all participants and by binding antibody multiplex assay (BAMA) thereafter in 60 participants (10 per treatment group) through Day 784. Compartmental population pharmacokinetic (PK) analyses were conducted to evaluate the VRC07-523LS serum pharmacokinetics. Neutralization activity was measured in a TZM-bl assay and anti-drug antibodies (ADA) were assayed using a tiered bridging assay testing strategy. Results: Injections were well-tolerated, with mild pain or tenderness reported commonly in the SC and IM groups, and mild to moderate erythema or induration reported commonly in the SC groups. Infusions were generally well-tolerated, with infusion reactions reported in 3 of 20 participants in the 20 mg/kg IV group. Peak geometric mean (GM) concentrations (95% confidence intervals) following the first administration were 29.0 µg/mL (25.2, 33.4), 58.5 µg/mL (49.4, 69.3), and 257.2 µg/mL (127.5, 518.9) in T1-T3 with IV dosing; 10.8 µg/mL (8.8, 13.3) and 22.8 µg/mL (20.1, 25.9) in T4-T5 with SC dosing; and 16.4 µg/mL (14.7, 18.2) in T6 with IM dosing. Trough GM concentrations immediately prior to the second administration were 3.4 µg/mL (2.5, 4.6), 6.5 µg/mL (5.6, 7.5), and 27.2 µg/mL (23.9, 31.0) with IV dosing; 0.97 µg/mL (0.65, 1.4) and 3.1 µg/mL (2.2, 4.3) with SC dosing, and 2.6 µg/mL (2.05, 3.31) with IM dosing. Peak VRC07-523LS serum concentrations increased linearly with the administered dose. At a given dose, peak and trough concentrations, as well as serum neutralization titres, were highest in the IV groups, reflecting the lower bioavailability following SC and IM administration. A single participant was found to have low titre ADA at a lone timepoint. VRC07-523LS has an estimated mean half-life of 42 days (95% CI: 40.5, 43.5), approximately twice as long as VRC01. Conclusions: VRC07-523LS was safe and well-tolerated across a range of doses and routes and is a promising long-acting bnAb for inclusion in HIV-1 prevention regimens.
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Durable humoral immunity is mediated by long-lived plasma cells (LLPCs) that reside in the bone marrow. It remains unclear whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein vaccination is able to elicit and maintain LLPCs. Here, we describe a sensitive method to identify and isolate antigen-specific LLPCs by tethering antibodies secreted by these cells onto the cell surface. Using this method, we found that two doses of adjuvanted SARS-CoV-2 spike protein vaccination are able to induce spike protein-specific LLPC reservoirs enriched for receptor binding domain specificities in the bone marrow of nonhuman primates that are detectable for several months after vaccination. Immunoglobulin gene sequencing confirmed that several of these LLPCs were clones of memory B cells elicited 2 weeks after boost that had undergone further somatic hypermutation. Many of the antibodies secreted by these LLPCs also exhibited improved neutralization and cross-reactivity compared with earlier time points. These findings establish our method as a means to sensitively and reliably detect rare antigen-specific LLPCs and demonstrate that adjuvanted SARS-CoV-2 spike protein vaccination establishes spike protein-specific LLPC reservoirs.
Assuntos
COVID-19 , Glicoproteína da Espícula de Coronavírus , Animais , Humanos , Plasmócitos/metabolismo , Anticorpos Antivirais , SARS-CoV-2 , COVID-19/prevenção & controle , Vacinação , Adjuvantes Imunológicos , Primatas , Anticorpos NeutralizantesRESUMO
HIV gp120 engineered outer domain germline-targeting version 8 (eOD-GT8) was designed specifically to engage naive B cell precursors of VRC01-class antibodies. However, the frequency and affinity of naive B cell precursors able to recognize eOD-GT8 have been evaluated only in U.S. populations. HIV infection is disproportionally concentrated in sub-Saharan Africa, so we seek to characterize naive B cells able to recognize eOD-GT8 in sub-Saharan cohorts. We demonstrate that people from sub-Saharan Africa have a higher or equivalent frequency of naive B cells able to engage eOD-GT8 compared with people from the U.S. Genetically, the higher frequency of eOD-GT8-positive cells is accompanied by a higher level of naive B cells with gene signatures characteristic of the VRC01 class, as well as other CD4bs-directed antibodies. Our study demonstrates that vaccination with eOD-GT8 in sub-Saharan Africa could be successful at expanding and establishing a pool of CD4bs-directed memory B cells from naive precursors.
Assuntos
Infecções por HIV , HIV-1 , Humanos , Anticorpos Neutralizantes , Anticorpos Anti-HIV , Células Precursoras de Linfócitos B , Proteína gp120 do Envelope de HIVRESUMO
The COVE trial randomized participants to receive two doses of mRNA-1273 vaccine or placebo on Days 1 and 29 (D1, D29). Anti-SARS-CoV-2 Spike IgG binding antibodies (bAbs), anti-receptor binding domain IgG bAbs, 50% inhibitory dilution neutralizing antibody (nAb) titers, and 80% inhibitory dilution nAb titers were measured at D29 and D57. We assessed these markers as correlates of protection (CoPs) against COVID-19 using stochastic interventional vaccine efficacy (SVE) analysis and principal surrogate (PS) analysis, frameworks not used in our previous COVE immune correlates analyses. By SVE analysis, hypothetical shifts of the D57 Spike IgG distribution from a geometric mean concentration (GMC) of 2737 binding antibody units (BAU)/mL (estimated vaccine efficacy (VE): 92.9% (95% CI: 91.7%, 93.9%)) to 274 BAU/mL or to 27,368 BAU/mL resulted in an overall estimated VE of 84.2% (79.0%, 88.1%) and 97.6% (97.4%, 97.7%), respectively. By binary marker PS analysis of Low and High subgroups (cut-point: 2094 BAU/mL), the ignorance interval (IGI) and estimated uncertainty interval (EUI) for VE were [85%, 90%] and (78%, 93%) for Low compared to [95%, 96%] and (92%, 97%) for High. By continuous marker PS analysis, the IGI and 95% EUI for VE at the 2.5th percentile (519.4 BAU/mL) vs. at the 97.5th percentile (9262.9 BAU/mL) of D57 Spike IgG concentration were [92.6%, 93.4%] and (89.2%, 95.7%) vs. [94.3%, 94.6%] and (89.7%, 97.0%). Results were similar for other D29 and D57 markers. Thus, the SVE and PS analyses additionally support all four markers at both time points as CoPs.
Assuntos
Vacina de mRNA-1273 contra 2019-nCoV , COVID-19 , Humanos , Anticorpos Neutralizantes , Anticorpos Antivirais , COVID-19/prevenção & controle , Imunoglobulina G , Eficácia de VacinasRESUMO
Influenza A virus subtype H2N2, which caused the 1957 influenza pandemic, remains a global threat. A recent phase I clinical trial investigating a ferritin nanoparticle displaying H2 hemagglutinin in H2-naïve and H2-exposed adults. Therefore, we could perform comprehensive structural and biochemical characterization of immune memory on the breadth and diversity of the polyclonal serum antibody response elicited after H2 vaccination. We temporally map the epitopes targeted by serum antibodies after first and second vaccinations and show previous H2 exposure results in higher responses to the variable head domain of hemagglutinin while initial responses in H2-naïve participants are dominated by antibodies targeting conserved epitopes. We use cryo-EM and monoclonal B cell isolation to describe the molecular details of cross-reactive antibodies targeting conserved epitopes on the hemagglutinin 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.
RESUMO
The lymph node (LN) is a critical biological site for immune maturation after vaccination as it includes several cell populations critical for priming the antibody response. Here, we present a protocol for sampling the LN and isolating cell populations to evaluate immunogens targeting germline cells. We describe steps for media and tube preparation and sample collection using an ultrasound-guided LN fine-needle aspiration procedure. This protocol is safe, quick, low-cost, and less invasive than excisional biopsy. For complete details on the use and execution of this protocol, please refer to Leggat et al. (2022).1.
Assuntos
Centro Germinativo , Linfonodos , Humanos , Biópsia por Agulha Fina , Linfonodos/diagnóstico por imagem , Linfonodos/patologia , Vacinação , Ultrassonografia de IntervençãoRESUMO
Soluble HIV-1-envelope (Env) trimers elicit immune responses that target their solvent-exposed protein bases, the result of removing these trimers from their native membrane-bound context. To assess whether glycosylation could limit these base responses, we introduced sequons encoding potential N-linked glycosylation sites (PNGSs) into base-proximal regions. Expression and antigenic analyses indicated trimers bearing six-introduced PNGSs to have reduced base recognition. Cryo-EM analysis revealed trimers with introduced PNGSs to be prone to disassembly and introduced PNGS to be disordered. Protein-base and glycan-base trimers induced reciprocally symmetric ELISA responses, in which only a small fraction of the antibody response to glycan-base trimers recognized protein-base trimers and vice versa. EM polyclonal epitope mapping revealed glycan-base trimers -even those that were stable biochemically- to elicit antibodies that recognized disassembled trimers. Introduced glycans can thus mask the protein base but their introduction may yield neo-epitopes that dominate the immune response.
RESUMO
BACKGROUND: Sudan Ebola virus can cause severe viral disease, with an average case fatality rate of 54%. A recent outbreak of Sudan Ebola virus in Uganda caused 55 deaths among 164 confirmed cases in the second half of 2022. Although vaccines and therapeutics specific for Zaire Ebola virus have been approved for use during outbreak situations, Sudan Ebola virus is an antigenically distinct virus with no approved vaccines available. METHODS: In this phase 1, open-label, dose-escalation trial we evaluated the safety, tolerability, and immunogenicity of a monovalent chimpanzee adenovirus 3 vaccine against Sudan Ebola virus (cAd3-EBO S) at Makerere University Walter Reed Project in Kampala, Uganda. Study participants were recruited from the Kampala metropolitan area using International Review Board-approved written and electronic media explaining the trial intervention. Healthy adults without previous receipt of Ebola, Marburg, or cAd3 vectored-vaccines were enrolled to receive cAd3-EBO S at either 1 × 1010 or 1 × 1011 particle units (PU) in a single intramuscular vaccination and were followed up for 48 weeks. Primary safety and tolerability endpoints were assessed in all vaccine recipients by reactogenicity for the first 7 days, adverse events for the first 28 days, and serious adverse events throughout the study. Secondary immunogenicity endpoints included evaluation of binding antibody and T-cell responses against the Sudan Ebola virus glycoprotein, and neutralising antibody responses against the cAd3 vector at 4 weeks after vaccination. This study is registered with ClinicalTrials.gov, NCT04041570, and is completed. FINDINGS: 40 healthy adults were enrolled between July 22 and Oct 1, 2019, with 20 receiving 1 × 1010 PU and 20 receiving 1 × 1011 PU of cAd3-EBO S. 38 (95%) participants completed all follow-up visits. The cAd3-EBO S vaccine was well tolerated with no severe adverse events. The most common reactogenicity symptoms were pain or tenderness at the injection site (34 [85%] of 40), fatigue (29 [73%] of 40), and headache (26 [65%] of 40), and were mild to moderate in severity. Positive responses for glycoprotein-specific binding antibodies were induced by 2 weeks in 31 (78%) participants, increased to 34 (85%) participants by 4 weeks, and persisted to 48 weeks in 31 (82%) participants. Most participants developed glycoprotein-specific T-cell responses (20 [59%, 95% CI 41-75] of 34; six participants were removed from the T cell analysis after failing quality control parameters) by 4 weeks after vaccination, and neutralising titres against the cAd3 vector were also increased from baseline (90% inhibitory concentration of 47, 95% CI 30-73) to 4 weeks after vaccination (196, 125-308). INTERPRETATION: The cAd3-EBO S vaccine was safe at both doses, rapidly inducing immune responses in most participants after a single injection. The rapid onset and durability of the vaccine-induced antibodies make this vaccine a strong candidate for emergency deployment in Sudan Ebola virus outbreaks. FUNDING: National Institutes of Health via interagency agreement with Walter Reed Army Institute of Research.
Assuntos
Adenovirus dos Símios , Vacinas contra Ebola , Ebolavirus , Doença pelo Vírus Ebola , Animais , Humanos , Adulto , Doença pelo Vírus Ebola/prevenção & controle , Pan troglodytes , Uganda , Sudão , Ebolavirus/genética , Anticorpos Antivirais , Adenovirus dos Símios/genética , Adenoviridae/genética , Glicoproteínas , Imunogenicidade da Vacina , Método Duplo-CegoRESUMO
Despite the availability of seasonal vaccines and antiviral medications, influenza virus continues to be a major health concern and pandemic threat due to the continually changing antigenic regions of the major surface glycoprotein, hemagglutinin (HA). One emerging strategy for the development of more efficacious seasonal and universal influenza vaccines is structure-guided design of nanoparticles that display conserved regions of HA, such as the stem. Using the H1 HA subtype to establish proof of concept, we found that tandem copies of an alpha-helical fragment from the conserved stem region (helix-A) can be displayed on the protruding spikes structures of a capsid scaffold. The stem region of HA on these designed chimeric nanoparticles is immunogenic and the nanoparticles are biochemically robust in that heat exposure did not destroy the particles and immunogenicity was retained. Furthermore, mice vaccinated with H1-nanoparticles were protected from lethal challenge with H1N1 influenza virus. By using a nanoparticle library approach with this helix-A nanoparticle design, we show that this vaccine nanoparticle construct design could be applicable to different influenza HA subtypes. Importantly, antibodies elicited by H1, H5, and H7 nanoparticles demonstrated homosubtypic and heterosubtypic cross-reactivity binding to different HA subtypes. Also, helix-A nanoparticle immunizations were used to isolate mouse monoclonal antibodies that demonstrated heterosubtypic cross-reactivity and provided protection to mice from viral challenge via passive-transfer. This tandem helix-A nanoparticle construct represents a novel design to display several hundred copies of non-trimeric conserved HA stem epitopes on vaccine nanoparticles. This design concept provides a new approach to universal influenza vaccine development strategies and opens opportunities for the development of nanoparticles with broad coverage over many antigenically diverse influenza HA subtypes.
Assuntos
Vírus da Influenza A Subtipo H1N1 , Vacinas contra Influenza , Influenza Humana , Nanopartículas , Animais , Camundongos , Humanos , Hemaglutininas , Epitopos , Formação de AnticorposRESUMO
Elicitation of antibodies that neutralize the tier-2 neutralization-resistant isolates that typify HIV-1 transmission has been a long-sought goal. Success with prefusion-stabilized envelope trimers eliciting autologous neutralizing antibodies has been reported in multiple vaccine-test species, though not in humans. To investigate elicitation of HIV-1 neutralizing antibodies in humans, here, we analyze B cells from a phase I clinical trial of the "DS-SOSIP"-stabilized envelope trimer from strain BG505, identifying two antibodies, N751-2C06.01 and N751-2C09.01 (named for donor-lineage.clone), that neutralize the autologous tier-2 strain, BG505. Though derived from distinct lineages, these antibodies form a reproducible antibody class that targets the HIV-1 fusion peptide. Both antibodies are highly strain specific, which we attribute to their partial recognition of a BG505-specific glycan hole and to their binding requirements for a few BG505-specific residues. Prefusion-stabilized envelope trimers can thus elicit autologous tier-2 neutralizing antibodies in humans, with initially identified neutralizing antibodies recognizing the fusion-peptide site of vulnerability.