Convergent antibody responses associated with broad neutralization of hepatitis C virus and clearance of infection

Early development of broadly neutralizing antibodies (bNAbs) targeting the hepatitis C virus (HCV) envelope glycoprotein E2 is associated with spontaneous clearance of infection, so induction of bNAbs is a major goal of HCV vaccine development. However, much remains to be learned at a molecular level about protective E2-specific antibodies, since HCV infection persists in some individuals despite early development of broadly neutralizing plasma. To examine B cell repertoire features associated with broad neutralization and viral clearance, we performed RNA sequencing of the B cell receptors (BCRs) of HCV E2-specific B cells of people with cleared or persistent HCV, including subjects with high or low plasma neutralizing breadth in both clearance and persistence groups. We identified many E2-specific public BCR clonotypes, which are antibody clones with the same V and J-genes and identical CDR3 sequences, shared among subjects grouped by either clearance or neutralization status. The majority (89) of these public clonotypes were shared by two subjects with broad plasma neutralizing activity and cleared infection, but not found in subjects with high plasma neutralizing breadth and persistent infection. We cloned a potent, cross-reactive neutralizing monoclonal antibody (mAb) by pairing the most abundant public heavy and light chains from these two subjects, providing evidence that broadly E2-reactive public clonotypes arise in a subset of individuals with broadly neutralizing plasma and spontaneous clearance of infection. Further characterization of the molecular features and function of these antibodies can inform HCV vaccine development.