Abstract
HIV-1 continues to pose a significant global health challenge, requiring ongoing research into effective prevention and treatment strategies. Understanding the B-cell repertoire that can be engaged upon vaccination in humans is crucial for the development of future preventive vaccines. In this study, peripheral blood mononuclear cells from HIV-negative participants in the multivalent HVTN124 human HIV-1 vaccine clinical trial were interrogated for HIV-reactive B cells using LIBRA-seq, a high-throughput B-cell mapping technology. We report the discovery of glycan-reactive antibodies, with one of these being capable of neutralizing diverse heterologous HIV-1 virus strains. Furthermore, isolated antibodies showed broad cross-reactivity against antigens from a variety of other pathogens. The emerging class of glycan-reactive virus-neutralizing antibodies with exceptional breadth of pathogen cross-reactivity may present an effective target for vaccination at the population level. IMPORTANCE: Understanding how the human immune system recognizes and combats viruses is crucial for developing better vaccines and treatments. Here, through characterization of the B-cell receptor repertoires of participants in HVTN124, a multivalent HIV-1 vaccine human clinical trial, we discovered antibodies that recognize sugar molecules (glycans) on antigens from a range of unrelated viral families. In addition to their binding breadth, these antibodies can also neutralize multiple diverse strains of HIV-1. Our findings reveal an emerging and underappreciated mechanism for antibodies to counteract virus infection, potentially opening doors for developing vaccines that preferentially elicit glycan-reactive antibody species to broadly protect against different viruses.This study is registered with ClinicalTrials.gov as NCT03409276.