BACKGROUND:Broadly neutralising antibodies (bNAbs) have shown promise as both prevention and treatment strategies against HIV-1. The clinical effectiveness of bNAbs depends on enhancing their neutralisation breadth and extending their serum half-lives. In this study, we aimed to assess the safety, tolerability, pharmacokinetic profile, and neutralisation activity in serum of N6LS, a HIV-1 bNAb. METHODS:In this first-in-human, dose-escalation, open-label, phase 1 trial, healthy adult participants (aged 18-50 years) who were HIV-1 negative were recruited to the National Institutes of Health Clinical Center (Bethesda, MD, USA). Three groups received one intravenous administration of N6LS at 5 mg/kg (n=3), 20 mg/kg (n=3), or 40 mg/kg (n=3); one group received one subcutaneous administration of 5 mg/kg N6LS (n=3); two groups received three administrations of either 5 mg/kg subcutaneous (n=5) or 20 mg/kg intravenous (n=5) N6LS every 12 weeks; and two groups received one subcutaneous administration of either 5 mg/kg (n=5) or 20 mg/kg (n=5) N6LS with ENHANZE drug product (EDP), recombinant human hyaluronidase PH20. The primary objectives were the safety and tolerability of N6LS with and without EDP. All participants who received N6LS were included in the primary safety analyses. This trial is registered at ClinicalTrials.gov, NCT03538626, and is complete. FINDINGS:Between June 18, 2018, and April 11, 2022, we enrolled 33 healthy adults (19 female individuals and 14 male individuals). One participant did not receive N6LS and one participant was lost to follow-up after 8 weeks. N6LS had an encouraging safety profile similar to other HIV-1 bNAbs, with no serious adverse events. Local reactogenicity was observed after administration of N6LS, with the most common symptom being mild to moderate injection site pain or tenderness in subcutaneous groups, reported in six of eight participants. All ten participants who received N6LS with EDP had mild to severe injection site erythema, which, despite being graded as severe in size, was generally not noticed by participants or deemed bothersome, and resolved without intervention. Systemic reactogenicity was mild in all groups. N6LS had an overall mean serum half-life of 48·6 days and retained its broad and potent neutralisation characteristics in serum. EDP administration increased N6LS bioavailability. No functional anti-drug antibodies to N6LS were detected following administration. INTERPRETATION:N6LS showed a promising safety and pharmacokinetics profile while retaining its potent neutralisation characteristics in serum, making it a promising candidate for inclusion in HIV-1 prevention and therapeutic combination strategies. The addition of EDP can enable safe subcutaneous administration of higher doses and larger volumes of N6LS, supporting additional methods for prophylactic and therapeutic bNAb administration. FUNDING:US National Institute of Allergy and Infectious Diseases Intramural Research Program, National Institutes of Health.

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.

Ebola virus disease (EVD) is a filoviral infection caused by virus species of the Ebolavirus genus including Zaire ebolavirus (EBOV) and Sudan ebolavirus (SUDV). We investigated the safety and immunogenicity of a heterologous prime-boost regimen involving a chimpanzee adenovirus 3 vectored Ebola vaccine [either monovalent (cAd3-EBOZ) or bivalent (cAd3-EBO)] prime followed by a recombinant modified vaccinia virus Ankara EBOV vaccine (MVA-EbolaZ) boost in two phase 1/1b randomized open-label clinical trials in healthy adults in the United States (US) and Uganda (UG). Trial US (NCT02408913) enrolled 140 participants, including 26 EVD vaccine-naïve and 114 cAd3-Ebola-experienced participants (April-November 2015). Trial UG (NCT02354404) enrolled 90 participants, including 60 EVD vaccine-naïve and 30 DNA Ebola vaccine-experienced participants (February-April 2015). All tested vaccines and regimens were safe and well tolerated with no serious adverse events reported related to study products. Solicited local and systemic reactogenicity was mostly mild to moderate in severity. The heterologous prime-boost regimen was immunogenic, including induction of durable antibody responses which peaked as early as two weeks and persisted up to one year after each vaccination. Different prime-boost intervals impacted the magnitude of humoral and cellular immune responses. The results from these studies demonstrate promising implications for use of these vaccines in both prophylactic and outbreak settings.

Currently, licensed seasonal influenza vaccines display variable vaccine effectiveness, and there remains a need for novel vaccine platforms capable of inducing broader responses against viral protein domains conserved among influenza subtypes. We conducted a first-in-human, randomized, open-label, phase 1 clinical trial ( NCT03186781 ) to evaluate a novel ferritin (H2HA-Ferritin) nanoparticle influenza vaccine platform. The H2 subtype has not circulated in humans since 1968. Adults born after 1968 have been exposed to only the H1 subtype of group 1 influenza viruses, which shares a conserved stem with H2. Including both H2-naive and H2-exposed adults in the trial allowed us to evaluate memory responses against the conserved stem domain in the presence or absence of pre-existing responses against the immunodominant HA head domain. Fifty healthy participants 18–70 years of age received H2HA-Ferritin intramuscularly as a single 20-μg dose ( n = 5) or a 60-μg dose either twice in a homologous ( n = 25) prime-boost regimen or once in a heterologous ( n = 20) prime-boost regimen after a matched H2 DNA vaccine prime. The primary objective of this trial was to evaluate the safety and tolerability of H2HA-Ferritin either alone or in prime-boost regimens. The secondary objective was to evaluate antibody responses after vaccination. Both vaccines were safe and well tolerated, with the most common solicited symptom being mild headache after both H2HA-Ferritin ( n = 15, 22%) and H2 DNA ( n = 5, 25%). Exploratory analyses identified neutralizing antibody responses elicited by the H2HA-Ferritin vaccine in both H2-naive and H2-exposed populations. Furthermore, broadly neutralizing antibody responses against group 1 influenza viruses, including both seasonal H1 and avian H5 subtypes, were induced in the H2-naive population through targeting the HA stem. This ferritin nanoparticle vaccine technology represents a novel, safe and immunogenic platform with potential application for pandemic preparedness and universal influenza vaccine development.

Background Multiple active vaccination approaches have proven ineffective in reducing the substantial morbidity and mortality caused by respiratory syncytial virus (RSV) in infants and older adults (aged >= 65 years). A vaccine conferring a substantial and sustainable boost in neutralising activity is required to protect against severe RSV disease. To that end, we evaluated the safety and immunogenicity of DS-Cav1, a prefusion F subunit vaccine. Methods In this randomised, open-label, phase 1 clinical trial, the stabilised prefusion F vaccine DS-Cav1 was evaluated for dose, safety, tolerability, and immunogenicity in healthy adults aged 18-50 years at a single US site. Participants were assigned to receive escalating doses of either 50 mu g, 150 mu g, or 500 mu g DS-Cav1 at weeks 0 and 12, and were randomly allocated in a 1:1 ratio within each dose group to receive the vaccine with or without aluminium hydroxide (AlOH) adjuvant. After 71 participants had been randomised, the protocol was amended to allow some participants to receive a single vaccination at week 0. The primary objectives evaluated the safety and tolerability at every dose within 28 days following each injection. Neutralising activity and RSV F-binding antibodies were evaluated from week 0 to week 44 as secondary and exploratory objectives. Safety was assessed in all participants who received at least one vaccine dose; secondary and exploratory immunogenicity analysis included all participants with available data at a given visit. The trial is registered with ClinicalTrials.gov, NCT03049488, and is complete and no longer recruiting. Findings Between Feb 21, 2017, and Nov 29, 2018, 244 participants were screened for eligibility and 95 were enrolled to receive DS-Cav1 at the 50 mu g (n=30, of which n=15 with AlOH), 150 mu g (n=35, of which n=15 with AlOH), or 500 mu g (n=30, of which n=15 with AlOH) doses. DS-Cav1 was safe and well tolerated and no serious vaccine-associated adverse events deemed related to the vaccine were identified. DS-Cav1 vaccination elicited robust neutralising activity and binding antibodies by 4 weeks after a single vaccination (p<0middot0001 for F-binding and neutralising antibodies). In analyses of exploratory endpoints at week 44, pre-F-binding IgG and neutralising activity were significantly increased compared with baseline in all groups. At week 44, RSV A neutralising activity was 3middot1 fold above baseline in the 50 mu g group, 3middot8 fold in the 150 mu g group, and 4middot5 fold in the 500 mu g group (p<0middot0001). RSV B neutralising activity was 2middot8 fold above baseline in the 50 mu g group, 3middot4 fold in the 150 mu g group, and 3middot7 fold in the 500 mu g group (p<0middot0001). Pre-F-binding IgG remained significantly 3middot2 fold above baseline in the 50 mu g group, 3middot4 fold in the 150 mu g group, and 4middot0 fold in the 500 mu g group (p<0middot0001). Pre-F-binding serum IgA remained 4middot1 fold above baseline in the 50 mu g group, 4middot3 fold in the 150 mu g group, and 4middot8 fold in the 500 mu g group (p<0middot0001). Although a higher vaccine dose or second immunisation elicited a transient advantage compared with lower doses or a single immunisation, neither significantly impacted long-term neutralisation. There was no long-term effect of dose, number of vaccinations, or adjuvant on neutralising activity. Interpretation In this phase 1 study, DS-Cav1 vaccination was safe and well tolerated. DS-Cav1 vaccination elicited a robust boost in RSV F-specific antibodies and neutralising activity that was sustained above baseline for at least 44 weeks. A single low-dose of pre-F immunisation of antigen-experienced individuals might confer protection that extends throughout an entire RSV season. Funding The National Institutes of Allergy and Infectious Diseases. Copyright (c) 2021 Elsevier Ltd. All rights reserved.

BACKGROUND:Although mother-to-child human immunodeficiency virus (HIV) transmission has dramatically decreased with maternal antiretroviral therapy, breast milk transmission accounts for most of the 180 000 new infant HIV infections annually. Broadly neutralizing antibodies (bNAb) may further reduce transmission. METHODS:A Phase 1 safety and pharmacokinetic study was conducted: a single subcutaneous (SC) dose of 20 or 40 mg/kg (Dose Groups 1 and 2, respectively) of the bNAb VRC01 was administered to HIV-exposed infants soon after birth. Breastfeeding infants (Dose Group 3) received 40 mg/kg SC VRC01 after birth and then 20 mg/kg/dose SC monthly. All infants received appropriate antiretroviral prophylaxis. RESULTS:Forty infants were enrolled (21 in the United States, 19 in Africa). Subcutaneous VRC01 was safe and well tolerated with only mild-to-moderate local reactions, primarily erythema, which rapidly resolved. For multiple-dose infants, local reactions decreased with subsequent injections. VRC01 was rapidly absorbed after administration, with peak concentrations 1-6 days postdose. The 40 mg/kg dose resulted in 13 of 14 infants achieving the serum 50 micrograms (mcg)/mL target at day 28. Dose Group 3 infants maintained concentrations greater than 50 mcg/mL throughout breastfeeding. CONCLUSIONS:Subcutaneous VRC01 as single or multiple doses is safe and well tolerated in very young infants and is suitable for further study to prevent HIV transmission in infants.

BACKGROUND:VRC01 is a human IgG1 broadly neutralizing antibody (bnAb) that binds to the HIV-1 envelope glycoprotein. It is being evaluated in two ongoing Phase 2b trials, the first efficacy assessment of a passively-administered bnAb for HIV-1 prevention. HVTN 104 was a phase 1 trial of VRC01. SETTING:We measured serum concentrations and serum neutralization of VRC01 in 1079 longitudinal samples collected after passive administration of VRC01 in 84 HVTN 104 participants. As assays for measuring VRC01 serum neutralization titers are resource-intensive, we investigated approaches to predicting such titers. METHODS:Serum concentration was measured using an anti-idiotypic ELISA assay. Serum neutralization ID50 titers and in vitro neutralization potency IC50 of the VRC01 clinical lot were measured against Env-pseudoviruses. Three approaches were used to predict serum neutralization ID50 titers based on (1) observed serum concentration divided by IC50, (2) pharmacokinetics model-predicted serum concentration divided by IC50, and (3) joint modeling of the longitudinal serum concentrations and ID50 titers. RESULTS:All 3 approaches yielded satisfactory prediction of neutralization titers against viruses of varied sensitivities; the median fold differences (FDs) of observed-over-predicted ID50 titers were between 0.95 and 1.37. Approach 3 generally performed the best with fold differences between 0.95 and 0.99 and <82% mean squared prediction error relative to approach 1. Similar results were obtained for ID80 titers. CONCLUSION:VRC01 serum neutralization could be accurately predicted, especially when using pharmacokinetics models. The proposed prediction approaches could potentially save significant resources for the characterization of serum neutralization of VRC01, including for other bnAbs and bnAb combinations.

Importance Chikungunya virus (CHIKV) is a mosquito-borne Alphavirus prevalent worldwide. There are currently no licensed vaccines or therapies. Objective To evaluate the safety and tolerability of an investigational CHIKV virus-like particle (VLP) vaccine in endemic regions. Design, Setting, and Participants This was a randomized, placebo-controlled, double-blind, phase 2 clinical trial to assess the vaccine VRC-CHKVLP059-00-VP (CHIKV VLP). The trial was conducted at 6 outpatient clinical research sites located in Haiti, Dominican Republic, Martinique, Guadeloupe, and Puerto Rico. A total of 400 healthy adults aged 18 through 60 years were enrolled after meeting eligibility criteria. The first study enrollment occurred on November 18, 2015; the final study visit, March 6, 2018. Interventions Participants were randomized 1:1 to receive 2 intramuscular injections 28 days apart (20 µg, n = 201) or placebo (n = 199) and were followed up for 72 weeks. Main Outcomes and Measures The primary outcome was the safety (laboratory parameters, adverse events, and CHIKV infection) and tolerability (local and systemic reactogenicity) of the vaccine, and the secondary outcome was immune response by neutralization assay 4 weeks after second vaccination. Results Of the 400 randomized participants (mean age, 35 years; 199 [50%] women), 393 (98%) completed the primary safety analysis. All injections were well tolerated. Of the 16 serious adverse events unrelated to the study drugs, 4 (25%) occurred among 4 patients in the vaccine group and 12 (75%) occurred among 11 patients in the placebo group. Of the 16 mild to moderate unsolicited adverse events that were potentially related to the drug, 12 (75%) occurred among 8 patients in the vaccine group and 4 (25%) occurred among 3 patients in the placebo group. All potentially related adverse events resolved without clinical sequelae. At baseline, there was no significant difference between the effective concentration (EC50)-which is the dilution of sera that inhibits 50% infection in viral neutralization assay-geometric mean titers (GMTs) of neutralizing antibodies of the vaccine group (46; 95% CI, 34-63) and the placebo group (43; 95% CI, 32-57). Eight weeks following the first administration, the EC50 GMT in the vaccine group was 2005 (95% CI, 1680-2392) vs 43 (95% CI, 32-58; P < .001) in the placebo group. Durability of the immune response was demonstrated through 72 weeks after vaccination. Conclusions and Relevance Among healthy adults in a chikungunya endemic population, a virus-like particle vaccine compared with placebo demonstrated safety and tolerability. Phase 3 trials are needed to assess clinical efficacy. Trial Registration ClinicalTrials.gov Identifier: NCT02562482.

Infusion of the broadly neutralizing antibody VRC01 has been evaluated in individuals chronically infected with HIV-1. Here, we studied how VRC01 infusions affected viral rebound after cessation of antiretroviral therapy (ART) in 18 acutely treated and durably suppressed individuals. Viral rebound occurred in all individuals, yet VRC01 infusions modestly delayed rebound and participants who showed a faster decay of VRC01 in serum rebounded more rapidly. Participants with strains most sensitive to VRC01 or with VRC01 epitope motifs similar to known VRC01-susceptible strains rebounded later. Upon rebound, HIV-1 sequences were indistinguishable from those sampled at diagnosis. Across the cohort, participant-derived Env showed different sensitivity to VRC01 neutralization (including 2 resistant viruses), yet neutralization sensitivity was similar at diagnosis and after rebound, indicating the lack of selection for VRC01 resistance during treatment interruption. Our results showed that viremia rebounded despite the absence of HIV-1 adaptation to VRC01 and an average VRC01 trough of 221 μg/mL. Although VRC01 levels were insufficient to prevent a resurgent infection, knowledge that they did not mediate Env mutations in acute-like viruses is relevant for antibody-based strategies in acute infection.

Background HIV-1-specific broadly neutralising antibodies such as VRC01 could promote HIV remission by halting viral replication and clearing infected cells. We investigated whether VRC01 could promote sustained viral control off antiretroviral therapy (ART) in adults who initiated ART during acute HIV infection. Methods We did a randomised, double-blind, placebo-controlled trial at the Thai Red Cross AIDS Research Centre in Bangkok, Thailand. Eligible participants were aged 20-50 years, had initiated ART during acute infection (ie, Fiebig stages I-III), had been taking ART for more than 24 months, had fewer than 50 HIV-1 RNA copies per mL on three consecutive measurements, had more than 400 CD4 cells per mu L, had fewer than ten copies of integrated HIV-1 DNA per 106 peripheral blood mononuclear cells, and were in generally good health. Eligible participants were randomly assigned (3: 1) based on computer-generated lists with a blocking factor of 4 to receive VRC01 (40 mg/kg) or placebo (saline) intravenously every 3 weeks for up to 24 weeks during analytic interruption of ART, followed by continued observation off all therapies. Randomisation was stratified by Fiebig stage (I vs II vs III) at HIV diagnosis. Participants were monitored closely and resumed ART if 1000 or more HIV-1 RNA copies were detected per mL of plasma. The primary outcomes were the frequency of serious adverse events and the proportion of participants with fewer than 50 HIV-1 RNA copies per mL 24 weeks after treatment interruption. Efficacy analyses included all participants who received at least one full dose of study product, and safety analyses included all participants exposed to any study product. The trial was registered with ClinicalTrials. gov, number NCT02664415. This trial is completed. Findings Between Aug 8, 2016, and Jan 9, 2017, 19 men were randomly assigned, 14 to the VRC01 group and five to the placebo group. One participant in the VRC01 group received a partial infusion without undergoing treatment interruption. The other 18 participants all received at least one full study infusion and underwent ART interruption. No serious adverse events were reported in either group. Only one participant in the VRC01 group achieved the primary efficacy endpoint of viral suppression 24 weeks after ART interruption. The other 17 restarted ART because of a confirmed recording of 1000 or more HIV-1 RNA copies per mL before 24 weeks. Interpretation VRC01 monotherapy in individuals who initiated ART during acute HIV infection was well tolerated but did not significantly increase the number of participants with viral suppression 24 weeks after ART interruption. Further development of VRC01 and other immunotherapies for HIV will probably occur as part of combination regimens that include several treatments directed against unique therapeutic targets.

Background mAb114 is a single monoclonal antibody that targets the receptor-binding domain of Ebola virus glycoprotein, which prevents mortality in rhesus macaques treated after lethal challenge with Zaire ebolavirus. Here we present expedited data from VRC 608, a phase 1 study to evaluate mAb114 safety, tolerability, pharmacokinetics, and immunogenicity. Methods In this phase 1, dose-escalation study (VRC 608), conducted at the US National Institutes of Health (NIH) Clinical Center (Bethesda, MD, USA), healthy adults aged 18-60 years were sequentially enrolled into three mAb114 dose groups of 5 mg/kg, 25 mg/kg, and 50 mg/kg. The drug was given to participants intravenously over 30 min, and participants were followed for 24 weeks. Participants were only enrolled into increased dosing groups after interim safety assessments. Our primary endpoints were safety and tolerability, with pharmacokinetic and anti-drug antibody assessments as secondary endpoints. We assessed safety and tolerability in all participants who received study drug by monitoring clinical laboratory data and self-report and direct clinician assessment of prespecified infusion-site symptoms 3 days after infusion and systemic symptoms 7 days after infusion. Unsolicited adverse events were recorded for 28 days. Pharmacokinetic and anti-drug antibody assessments were completed in participants with at least 56 days of data. This trial is registered with ClinicalTrials. gov, number NCT03478891, and is active but no longer recruiting. Findings Between May 16, and Sept 27, 2018, 19 eligible individuals were enrolled. One (5%) participant was not infused because intravenous access was not adequate. Of 18 (95%) remaining participants, three (17%) were assigned to the 5 mg/kg group, five (28%) to the 25 mg/kg group, and ten (55%) to the 50 mg/kg group, each of whom received a single infusion of mAb114 at their assigned dose. All infusions were well tolerated and completed over 30-37 min with no infusion reactions or rate adjustments. All participants who received the study drug completed the safety assessment of local and systemic reactogenicity. No participants reported infusion-site symptoms. Systemic symptoms were all mild and present only in four (22%) of 18 participants across all dosing groups. No unsolicited adverse events occurred related to mAb114 and one serious adverse event occurred that was unrelated to mAb114. mAb114 has linear pharmacokinetics and a half-life of 24.2 days (standard error of measurement 0.2) with no evidence of anti-drug antibody development. Interpretation mAb114 was well tolerated, showed linear pharmacokinetics, and was easily and rapidly infused, making it an attractive and deployable option for treatment in outbreak settings. Funding Vaccine Research Center, US National Institute of Allergy and Infectious Diseases, and NIH. Copyright (c) 2019 Elsevier Ltd. All rights reserved.

Lineage-based vaccine design is an attractive approach for eliciting broadly neutralizing antibodies (bNAbs) against HIV-1. However, most bNAb lineages studied to date have features indicative of unusual recombination and/or development. From an individual in the prospective RV217 cohort, we identified three lineages of bNAbs targeting the membrane-proximal external region (MPER) of the HIV-1 envelope. Antibodies RV217-VRC42.01, -VRC43.01, and -VRC46.01 used distinct modes of recognition and neutralized 96%, 62%, and 30%, respectively, of a 208-strain virus panel. All three lineages had modest levels of somatic hypermutation and normal antibody-loop lengths and were initiated by the founder virus MPER. The broadest lineage, VRC42, was similar to the known bNAb 4E10. A multimeric immunogen based on the founder MPER activated B cells bearing the unmutated common ancestor of VRC42, with modest maturation of early VRC42 intermediates imparting neutralization breadth. These features suggest that VRC42 may be a promising template for lineage-based vaccine design.

The vaccine-mediated elicitation of antibodies (Abs) capable of neutralizing diverse HIV-1 strains has been a long-standing goal. To understand how broadly neutralizing antibodies (bNAbs) can be elicited, we identified, characterized, and tracked five neutralizing Ab lineages targeting the HIV-1-fusion peptide (FP) in vaccinated macaques over time. Genetic and structural analyses revealed two of these lineages to belong to a reproducible class capable of neutralizing up to 59% of 208 diverse viral strains. B cell analysis indicated each of the five lineages to have been initiated and expanded by FP-carrier priming, with envelope (Env)-trimer boosts inducing cross-reactive neutralization. These Abs had binding-energy hotspots focused on FP, whereas several FP-directed Abs induced by immunization with Env trimer-only were less FP-focused and less broadly neutralizing. Priming with a conserved subregion, such as FP, can thus induce Abs with binding-energy hotspots coincident with the target subregion and capable of broad neutralization.

Induction of an antibody response capable of recognizing highly diverse strains is a major obstacle to the development of vaccines for viruses such as HIV and influenza. Here, we report the dynamics of B cell expansion and evolution at the single-cell level after vaccination with a replication-competent adenovirus type 4 recombinant virus expressing influenza H5 hemagglutinin. Fluorescent H1 or H5 probes were used to quantitate and isolate peripheral blood B cells and their antigen receptors. We observed increases in H5-specific antibody somatic hypermutation and potency for several months beyond the period of active viral replication that was not detectable at the serum level. Individual broad and potent antibodies could be isolated, including one stem-specific antibody that is part of a new multidonor class. These results demonstrate prolonged evolution of the B cell response for months after vaccination and should be considered in efforts to evaluate or boost vaccine-induced immunity.

Background Human monoclonal antibodies that potently and broadly neutralise HIV-1 are under development to prevent and treat HIV-1 infection. In this phase 1 clinical trial we aimed to determine the safety, tolerability, and pharmacokinetic profile of the broadly neutralising monoclonal antibody VRC07-523LS, an engineered variant of VRC01 that targets the CD4 binding site of the HIV-1 envelope protein. Methods This phase 1, open-label, dose-escalation clinical trial was done at the National Institutes of Health Clinical Center in Bethesda, MD, USA. Individuals were recruited from the greater Washington, DC, area by IRB-approved written and electronic media. We enrolled healthy, HIV-1-negative adults aged 18-50 years. Inclusion criteria were good general health, measured through clinical laboratory tests, medical history, and physical examination. Participants self-selected into one of seven open groups during enrolment without randomisation. Four groups received a single intravenous dose of 1, 5, 20, or 40 mg/kg of VRC07-523LS, and one group received a single 5 mg/kg subcutaneous dose. Two groups received three doses of either 20 mg/kg intravenous VRC07-523LS, or 5 mg/kg subcutaneous VRC07-523 LS at 12-week intervals. The primary outcome was the safety and tolerability of VRC07-523LS, assessed by dose, route, and number of administrations. This study is registered with ClinicalTrials.gov , NCT03015181. Findings Between Feb 21, 2017, and September 13, 2017, we enrolled 26 participants, including 11 (42%) men and 15 (58%) women. Two (8%) participants withdrew from the study early: one participant in group 1 enrolled in the study but never received VRC07-523LS, and one participant in group 6 chose to withdraw after a single administration. One (4%) participant in group 7 received only one of the three scheduled administrations. 17 participants received intravenous administrations and 8 participants received subcutaneous administrations. VRC07-523LS was safe and well tolerated, we observed no serious adverse events or dose-limiting toxic effects. All reported local and systemic reactogenicity was mild to moderate in severity. The most commonly reported symptoms following intravenous administration were malaise or myalgia in three (18%) participants and headache or chills in two (12%) participants. The most commonly reported symptoms following subcutaneous administration were pain and tenderness in four participants (50%) and malaise or headache in three (38%) participants. Interpretation Safe and well tolerated, VRC07-523LS is a strong and practical candidate for inclusion in HIV-1 prevention and therapeutic strategies. The results from this trial also indicate that an HIV-1 broadly neutralising monoclonal antibody engineered for improved pharmacokinetic and neutralisation properties can be safe for clinical use. Copyright (C) 2019 Elsevier Ltd. All rights reserved.

HIV- and SIV-envelope (Env) trimers are both extensively glycosylated, and antibodies identified to date have been unable to fully neutralize SIVmac239. Here, we report the isolation, structure, and glycan interactions of antibody ITS90.03, a monoclonal antibody that completely neutralized the highly neutralization-resistant isolate, SIVmac239. The co-crystal structure of a fully glycosylated SIVmac239-gp120 core in complex with rhesus CD4 and the antigen-binding fragment of ITS90.03 at 2.5-Å resolution revealed that ITS90 recognized an epitope comprised of 45% glycan. SIV-gp120 core, rhesus CD4, and their complex could each be aligned structurally to their human counterparts. The structure revealed that glycans masked most of the SIV Env protein surface, with ITS90 targeting a glycan hole, which is occupied in ∼83% of SIV strains by glycan N238. Overall, the SIV glycan shield appears to functionally resemble its HIV counterpart in coverage of spike, shielding from antibody, and modulation of receptor accessibility.

Broadly neutralizing antibodies (bNAbs) against HIV-1 envelope (Env) inform vaccine design and are potential therapeutic agents. We identified SF12 and related bNAbs with up to 62% neutralization breadth from an HIV-infected donor. SF12 recognized a glycan-dominated epitope on Env's silent face and was potent against clade AE viruses, which are poorly covered by V3-glycan bNAbs. A 3.3Å cryo-EM structure of a SF12-Env trimer complex showed additional contacts to Env protein residues by SF12 compared with VRC-PG05, the only other known donor-derived silentface antibody, explaining SF12's increased neutralization breadth, potency, and resistance to Env mutation routes. Asymmetric binding of SF12 was associated with distinct N-glycan conformations across Env protomers, demonstrating intra-Env glycan heterogeneity. Administrating SF12 to HIV-1-infected humanized mice suppressed viremia and selected for viruses lacking the N448gp120 glycan. Effective bNAbs can therefore be raised against HIV-1 Env's silent face, suggesting their potential for HIV-1 prevention, therapy, and vaccine development.

BackgroundSeasonal influenza results in significant morbidity and mortality worldwide, but the currently licensed inactivated vaccines generally have low vaccine efficacies and could be improved. In this phase 1 clinical trial, we compared seasonal influenza vaccine regimens with different priming strategies, prime-boost intervals, and administration routes to determine the impact of these variables on the resulting antibody response.MethodsBetween August 17, 2012 and January 25, 2013, four sites enrolled healthy adults 18-70 years of age. Subjects were randomized to receive one of the following vaccination regimens: trivalent hemagglutinin (HA) DNA prime followed by trivalent inactivated influenza vaccine (IIV3) boost with a 3.5 month interval (DNA-IIV3), IIV3 prime followed by IIV3 boost with a 10 month interval (IIV3-IIV3), or concurrent DNA and IIV3 prime followed by IIV3 boost with a 10 month interval (DNA/IIV3-IIV3). Each regimen was additionally stratified by an IIV3 administration route of either intramuscular (IM) or intradermal (ID). DNA vaccines were administered by a needle-free jet injector (Biojector). Study objectives included evaluating the safety and tolerability of each regimen and measuring the antibody response by hemagglutination inhibition (HAI).ResultsThree hundred and sixteen subjects enrolled. Local reactogenicity was mild to moderate in severity, with higher frequencies recorded following DNA vaccine administered by Biojector compared to IIV3 by either route (p <0.02 for pain, swelling, and redness) and following IIV3 by ID route compared to IM route (p <0.001 for swelling and redness). Systemic reactogenicity was similar between regimens. Though no overall differences were observed between regimens, the highest titers post boost were observed in the DNA-IIV3 group by ID route and in the IIV3-IIV3 group by IM route.ConclusionsAll vaccination regimens were found to be safe and tolerable. While there were no overall differences between regimens, the DNA-IIV3 group by ID route, and the IIV3-IIV3 group by IM route, showed higher responses compared to the other same-route regimens.