Kang C Y, Hariharan K, Nara P L, Sodroski J, Moore J P
IDEC Pharmaceuticals Corporation, San Diego, California 92121.
J Virol. 1994 Sep;68(9):5854-62. doi: 10.1128/JVI.68.9.5854-5862.1994.
Preservation of the conformation of recombinant gp120 in an adjuvant, enabling it to elicit conformation-dependent, epitope-specific, broadly neutralizing antibodies, may be critical for the development of any gp120-based human immunodeficiency virus type 1 (HIV-1) vaccine. It was hypothesized that recombinant gp120 complexed with recombinant CD4 could stabilize the conformation-dependent neutralizing epitopes and effectively deliver them to the immune system. Therefore, a soluble CD4-gp120 complex in Syntex adjuvant formulation was tested with mice for its ability to induce neutralizing anti-gp120 antibody responses. Seventeen monoclonal antibodies (MAbs) were generated and characterized. Immunochemical studies, neutralization assays, and mapping studies with gp120 mutants indicated that the 17 MAbs fell into three groups. Four of them were directed to what is probably a conformational epitope involving the C1 domain and did not possess virus-neutralizing activities. Another four MAbs bound to V3 peptide 302-321 and exhibited cross-reactive gp120 binding and relatively weak virus-neutralizing activities. These MAbs were very sensitive to amino acid substitutions, not only in the V3 regions but also in the base of the V1/V2 loop, implying a conformational constraint on the epitope. The last group of nine MAbs recognized conformation-dependent epitopes near the CD4 binding site of gp120 and inhibited the gp120-soluble CD4 interaction. Four of these nine MAbs showed broadly neutralizing activities against multiple laboratory-adapted strains of HIV-1, three of them neutralized only HIVIIIB, and the two lower-affinity MAbs did not neutralize any strain tested. Collectively, the results from this study indicate that immunization with the CD4-gp120 complex can elicit antibodies to conformationally sensitive gp120 epitopes, with some of the antibodies having broadly neutralizing activities. We suggest that immunization with CD4-gp120 complexes may be worth evaluating further for the development of an AIDS vaccine.
在佐剂中保持重组 gp120 的构象，使其能够引发构象依赖性、表位特异性、广泛中和抗体，这对于任何基于 gp120 的 1 型人类免疫缺陷病毒（HIV-1）疫苗的开发可能至关重要。据推测，与重组 CD4 复合的重组 gp120 可以稳定构象依赖性中和表位，并有效地将它们递送至免疫系统。因此，用 Syntex 佐剂配方中的可溶性 CD4-gp120 复合物对小鼠进行测试，以检测其诱导中和抗 gp120 抗体反应的能力。产生并鉴定了 17 种单克隆抗体（MAb）。免疫化学研究、中和试验以及对 gp120 突变体的定位研究表明，这 17 种 MAb 分为三组。其中四种针对可能涉及 C1 结构域的构象表位，不具有病毒中和活性。另外四种 MAb 与 V3 肽 302-321 结合，表现出交叉反应性 gp120 结合和相对较弱的病毒中和活性。这些 MAb 对氨基酸取代非常敏感，不仅在 V3 区域，而且在 V1/V2 环的基部，这意味着表位存在构象限制。最后一组的九种 MAb 识别 gp120 的 CD4 结合位点附近的构象依赖性表位，并抑制 gp120 与可溶性 CD4 的相互作用。这九种 MAb 中的四种对多种实验室适应的 HIV-1 毒株表现出广泛中和活性，其中三种仅中和 HIVIIIB，而两种低亲和力 MAb 未中和任何测试毒株。总体而言，本研究结果表明，用 CD4-gp120 复合物免疫可引发针对构象敏感的 gp120 表位的抗体，其中一些抗体具有广泛中和活性。我们建议，对于艾滋病疫苗的开发，用 CD4-gp120 复合物进行免疫可能值得进一步评估。
