Human herpesvirus 6B (HHV-6B), a β-herpesvirus that significantly threatens immunocompromised individuals, currently lacks targeted antiviral therapies or vaccines. Glycoprotein B (gB), the primary mediator of membrane fusion during viral entry, is a key target for neutralizing antibody (nAb) and vaccine development. In this study, we determined a 2.8 Å cryo-EM structure of the HHV-6B gB ectodomain in its postfusion conformation, unveiling unique N-terminal features and resolving the furin site for the first time in herpesviruses. Comparative analyses highlighted similarities between HHV-6B gB and gB from human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV), mapping conserved residues across herpesviruses. Cross-binding assays indicated minimal cross-epitope recognition by nAbs from other herpesviruses, while several potential vulnerable sites on HHV-6B gB were identified. These insights advance our understanding of HHV-6B infection mechanisms and support future development of antibodies or vaccines targeting gB.
Copyright: © 2025 Xie et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.