An effective HIV-1 vaccine must elicit broadly neutralizing antibodies (bnAbs) against highly diverse Envelope glycoproteins (Env). Since Env with the longest hypervariable (HV) loops is more resistant to the cognate bnAbs than Env with shorter HV loops, we redesigned hypervariable loops for updated Env consensus sequences of subtypes B and C and CRF01_AE. Using modeling with AlphaFold2, we reduced the length of V1, V2, and V5 HV loops while maintaining the integrity of the Env structure and glycan shield, and modified the V4 HV loop. Spacers are designed to limit strain-specific targeting. All updated Env are infectious as pseudoviruses. Preliminary structural characterization suggests that the modified HV loops have a limited impact on Env’s conformation. Binding assays show improved binding to modified subtype B and CRF01_AE Env but not to subtype C Env. Neutralization assays show increases in sensitivity to bnAbs, although not always consistently across clades. Strikingly, the HV loop modification renders the resistant CRF01_AE Env sensitive to 10-1074 despite the absence of a glycan at N332.

有效的 HIV-1 疫苗必须引发针对高度多样化的包膜糖蛋白 (Env) 的广泛中和抗体 (bnAb)。由于具有最长高变 (HV) 环的 Env 比具有较短 HV 环的 Env 对同源 bnAb 具有更强的抵抗力，因此我们重新设计了高变环，以更新亚型 B 和 C 以及 CRF01_AE 的 Env 共有序列。使用 AlphaFold2 建模，我们缩短了 V1、V2 和 V5 HV 环的长度，同时保持 Env 结构和聚糖屏蔽的完整性，并修改了 V4 HV 环。间隔物旨在限制菌株特异性靶向。所有更新的 Env 都具有伪病毒的传染性。初步结构表征表明，修饰的 HV 环对 Env 构象的影响有限。结合测定显示与修饰的 B 亚型和 CRF01_AE Env 的结合得到改善，但与 C 亚型 Env 的结合没有改善。中和测定显示对 bnAb 的敏感性有所增加，尽管各进化枝之间并不总是一致。引人注目的是，HV 环修饰使得抗性 CRF01_AE Env 对 10-1074 敏感，尽管 N332 处不存在聚糖。