Javaherian K, Langlois A J, Schmidt S, Kaufmann M, Cates N, Langedijk J P, Meloen R H, Desrosiers R C, Burns D P, Bolognesi D P
Repligen Corporation, Cambridge, MA 02139.
Proc Natl Acad Sci U S A. 1992 Feb 15;89(4):1418-22. doi: 10.1073/pnas.89.4.1418.
To identify the principal neutralization determinant (PND) of simian immunodeficiency virus (SIV), antisera were generated using recombinant gp110 [the SIV analog of the human immunodeficiency virus type 1 (HIV-1) external envelope glycoprotein, gp120], gp140, several large recombinant and proteolytic envelope fragments, and synthetic peptides of the SIVmac251 isolate. When purified under conditions that retain its native structure, gp110 bound CD4 and elicited antisera that neutralized SIVmac251 with high titer. Native gp110 also completely inhibited neutralizing antibody in sera from SIVmac251-infected macaques. In contrast, denatured gp110 and gp140, large envelope fragments, and synthetic peptides (including peptides analogous to the HIV-1 PND) elicited very low or undetectable neutralizing antibody titers and did not inhibit neutralizing antibody in infected macaque sera. Enzymatically deglycosylated gp110 efficiently absorbed neutralizing antibodies from macaque sera, showing that neutralizing antibodies primarily bind the protein backbone. A 45-kDa protease digest product, mapping to the carboxyl-terminal third of gp110, also completely absorbed neutralizing antibodies from infected macaque sera. These results show that the PND(s) of this SIV isolate depends on the native conformation and that linear peptides corresponding to the V3 loop of SIV envelope, in contrast to that of HIV-1, do not elicit neutralizing antibody. This may affect the usefulness of SIVmac for evaluating HIV-1 envelope vaccine approaches that rely on eliciting neutralizing antibody.
为了鉴定猴免疫缺陷病毒（SIV）的主要中和决定簇（PND），使用重组gp110[1型人类免疫缺陷病毒（HIV-1）外膜糖蛋白gp120的SIV类似物]、gp140、几个大型重组和蛋白水解包膜片段以及SIVmac251分离株的合成肽制备了抗血清。在保留其天然结构的条件下纯化时，gp110结合CD4并诱导出高效中和SIVmac251的抗血清。天然gp110还完全抑制了SIVmac251感染猕猴血清中的中和抗体。相比之下，变性的gp110和gp140、大型包膜片段以及合成肽（包括与HIV-1 PND类似的肽）诱导出的中和抗体效价极低或无法检测到，并且不能抑制感染猕猴血清中的中和抗体。酶促去糖基化的gp110能有效吸收猕猴血清中的中和抗体，表明中和抗体主要结合蛋白质骨架。一个45 kDa的蛋白酶消化产物，定位于gp110的羧基末端三分之一处，也能完全吸收感染猕猴血清中的中和抗体。这些结果表明，该SIV分离株的PND取决于天然构象，并且与HIV-1不同，对应于SIV包膜V3环的线性肽不会诱导中和抗体。这可能会影响SIVmac在评估依赖诱导中和抗体的HIV-1包膜疫苗方法中的实用性。
