Montefiori D C, Graham B S, Zhou J, Zhou J, Bucco R A, Schwartz D H, Cavacini L A, Posner M R
Department of Pathology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
J Clin Invest. 1993 Aug;92(2):840-7. doi: 10.1172/JCI116658.
Sera from 11 volunteers immunized with a recombinant HIV-1 gp160-expressing vaccinia virus (HIVAC-1e; Oncogen/Bristol-Myers Squibb, Seattle, WA) and boosted with baculovirus-derived rgp160 (VaxSyn; MicroGeneSys, Inc., Meriden, CT) were evaluated for functional serum antibodies and their epitopes. Sera obtained prior to boosting had undetectable HIV-1-specific IgG and neutralizing activity, and did not block HIV-1 from binding or fusing to CD4+ MT-2 cells. 14 d after boosting, sera from each volunteer contained HIV-1-specific IgG titers of 1:40 to 1:1,280. Five of these sera also contained neutralizing antibodies, where most or all neutralizing activity was blocked by a synthetic peptide corresponding to amino acids 307-330 of the V3 loop of gp120, indicating that neutralizing antibodies were mostly V3 loop-specific. All sera obtained after boosting contained HIV-1 binding/fusion-inhibition antibodies, and a significant portion of their activity was blocked by the V3 loop peptide, a result consistent with the presence of antibodies against the region of the V3 loop that participates in fusion. Three sera with V3 loop-specific neutralizing and fusion-inhibition antibodies were studied further. In competitive antibody binding experiments, antibodies reactive with the conformation-dependent, CD4 binding site of gp120 were undetectable in each serum. When evaluated in combination with a monoclonal antibody to the CD4 binding site of gp120, two sera demonstrated synergism in neutralizing assays, and all three sera demonstrated synergism in binding/fusion-inhibition assays, further indicating that the functional antibodies were primarily V3 loop-specific. The synergism also suggests that a vaccine that elicits strong serum antibody responses to both regions of gp120 may improve the potential for inducing protective immunity.
对11名志愿者的血清进行了评估，这些志愿者用表达重组HIV-1 gp160的痘苗病毒（HIVAC-1e；Oncogen/百时美施贵宝公司，华盛顿州西雅图）免疫，并以杆状病毒衍生的rgp160（VaxSyn；MicroGeneSys公司，康涅狄格州梅里登）加强免疫，以检测功能性血清抗体及其表位。加强免疫前获得的血清中未检测到HIV-1特异性IgG和中和活性，并且不能阻止HIV-1与CD4+ MT-2细胞结合或融合。加强免疫14天后，每名志愿者的血清中HIV-1特异性IgG滴度为1:40至1:1280。其中5份血清还含有中和抗体，大多数或所有中和活性被对应于gp120 V3环氨基酸307-330的合成肽阻断，表明中和抗体大多是V3环特异性的。加强免疫后获得的所有血清均含有HIV-1结合/融合抑制抗体，其大部分活性被V3环肽阻断，这一结果与存在针对参与融合的V3环区域的抗体一致。对3份具有V3环特异性中和及融合抑制抗体的血清进行了进一步研究。在竞争性抗体结合实验中，每份血清中均未检测到与gp120构象依赖性CD4结合位点反应的抗体。当与针对gp120 CD4结合位点的单克隆抗体联合评估时，2份血清在中和试验中表现出协同作用，所有3份血清在结合/融合抑制试验中均表现出协同作用，进一步表明功能性抗体主要是V3环特异性的。这种协同作用还表明，一种能引发针对gp120两个区域的强烈血清抗体反应的疫苗可能会提高诱导保护性免疫的潜力。
