EVALUATION OF SAFETY OF MONOCLONAL ANTIBODIES AGAINST HIV ENVELOPE AND ITS CELLUL

(1)项目目标：- 研究抗HIV-1包膜（gp 120）、CD 4、gp 120/CD 4复合物或HIV-1共受体的单克隆抗体（mAb）对HIV-1融合/感染原代人细胞的活性。- 检查此类mAb对原代人细胞正常生物学功能的影响。(2)实验方法：- 我们收集了一组对HIV-1 gp 120或CD 4分子具有特异性的鼠单克隆抗体，其以增加的亲合力与gp 120/CD 4复合物结合，并可能参与共受体募集。 - 检测这些mAb对HIV-1融合/感染（M-嗜性和T-嗜性毒株）的影响，以及在各种旨在测量gp 120、CD 4和HIV-1共受体之间三分子复合物形成的测定中的活性。(3)主要发现： - 针对可溶性gp 120（LAI）/CD 4复合物产生MAb CG 10。它是gp 120特异性的，但严格依赖于复合物。它最近被证明与gp 120中的区域相互作用，该区域“面对”并可能与靶细胞上的辅助受体分子相互作用。在融合/感染性试验中，我们发现CG 10 mAb不会阻断而是增强病毒融合。尽管在不同的最佳剂量下，T-嗜性和M-嗜性env介导的融合都得到增强。这些发现表明，单克隆抗体，如CG 10可能有有害的，而不是通过增加细胞间的病毒转移在体内的保护作用。 - 在HIV-1共受体（CXCR 4或CCR 5）募集的多项试验中，检测了与预先形成的CD 4/gp 120复合物结合的亲合力比与CD 4结合的亲合力高10倍的CD 4特异性mAb（CG 1、7、8）。在三种不同的测定中，发现这些mAb在三分子复合物中稳定共受体、gp 120和CD 4的缔合。这种抗体可以用作工具来检测导致HIV-1细胞进入的步骤。在体内，它们可能导致病毒细胞进入增加，从而导致病毒载量增加。

(1) Goals of project: - To study the activities of monoclonal antibodies (mAbs) raised against HIV-1 envelope (gp120), CD4, gp120/CD4 complexes, or the HIV-1 co-receptors, on HIV-1 fusion/infection of primary human cells. - To examine the effects of such mAbs on the normal biological functions of primary human cells. (2) Experimental approach: - We have collected a panel of murine mAbs specific for the HIV-1 gp 120 or for the CD4 molecules, that bind with increased avidity to the gp120/CD4 complex and may be involved in co-receptor recruitment. - These mAbs were tested for their effects on HIV-1 fusion/infection (both M-tropic and T-tropic strains), and for their activity in various assays designed to measure the formation of tri-molecular complexes between gp120,CD4, and the HIV-1 co-receptors. (3) Major Findings: - MAb CG10 was generated against soluble gp120(LAI)/CD4 complexes. It is gp120-specific but stricly complex-dependent. It was recently shown to interact with the region in gp120 that "faces" and possibly interact with the co-receptor molecules on target cells. In fusion/infectivity assays, we found that the CG10 mAb does not block but rather enhances viral fusion. Both T-tropic and M-tropic env-mediated fusion was enhanced, albeit at different optimal doses. These findings suggest that mAbs such as CG10 may have deleterious rather than protective effects in vivo by increasing cell-to-cell viral transfer. - CD4-specific mAbs (CG1,7,8) that bind with 10 fold higher avidity to preformed CD4/gp120 complexes than to CD4, were tested in multiple assays of HIV-1 co-receptor (CXCR4 or CCR5) recruitment. In three different assays these mAbs were found to stabilize the association of co-receptor, gp120, and CD4 in tri-molecular comlexes. Such antibodies may be used as tools to disect the steps leading to HIV-1 cell entry. In vivo, they may lead to an increase in viral-cell entry resulting in increased viral loads.