HIV-1中枢特征性突变的中和敏感性和免疫逃逸分析

Neutralization sensitivity and immune escape of HIV-1 CNS related mutations

目的检测HIV-1中枢特征性突变对中和抗体的中和敏感性,探讨其发生免疫逃逸的可能性.方法构建含有S446T、F396N、K429G、K337G、T319A、Q389K和N407T突变的HIV-1包膜假病毒,测定其感染靶细胞能力、对代表性广谱单克隆中和抗体PGT121、PGT135、VRC01、2G12、10E8和12A21的中和敏感性,分子构象模拟突变如何影响中和抗体的中和效果.结果 7种突变假病毒均能被VRC01、2G12和10E8中和,表现为高度敏感,对PGT121和12A21均不敏感;对PGT135,F396N高度敏感,S446T、K429G和T319A为中度敏感,而K337G、Q389K和N407T均不敏感.分子构象模拟Q389突变为K时,Q389 NE2氮原子与T415 O原子形成的氢键消失,氨基酸侧链折叠可导致空间位阻增加,影响389位作为可接触残基与PGT135相互作用.结论基于中枢特征性突变的HIV-1假病毒可发生免疫逃逸,突变病毒对PGT135中和敏感性降低.

Objective To investigate neutralization sensitivity of HIV-1 pseudoviruses with CNS related mutations on broadly monoclonal neutralizing antibodies (bmNAbs), and to explore the possibility of immune escape. Methods The pseudoviruses with HIV-1 CNS related mutations, including S446T, F396N, K429G, K337G, T319A, Q389K and N407T were constructed. The corresponding infectivity of above mutants, and the neutralization sensitivity in responding to bmNAbs, e.g. PGT121、PGT135、VRC01、2G12、10E8 and 12A21 were determined. Molecular docking was used to explore the effects of CNS-related residues of env proteins on antibody binding. Results All the pseudoviruses carrying 7 mutations were highly sensitive to neutralization by VRC01, 2G12 and 10E8, but were resistant to PGT121 and 12A21. As for PGT135, the pseudovirus containing the F396N mutant displayed highly sensitive to it, and S446T, K429G and T319A mutants showed moderately sensitive to this mutation type, but K337G, Q389K and N407T were resistant to PGT135. When the molecular conformational simulation of Q389 mutated to K, the hydrogen bond formed between the nitrogen atom of Q389 NE2 and the oxygen atom of T415 disappeared. The folding of the amino acid side chain may strengthen in steric hindrance, affecting the residue at position 389 as a contactable residue to interaction with PGT135. Conclusions HIV-1 pseudovirus with CNS-related mutations may undergo immune escape, which reduced neutralization sensitivity to PGT135 in some degree..