An approach for development of new drugs for AIDS which inhibit the novel receptor for AIDS virus

人类免疫缺陷病毒（HIV）感染是由于HIV包膜糖蛋白gp 120与T4^+淋巴细胞表面的CD 4分子相互作用介导的病毒-细胞融合。然而，CD 4分子可能不是HIV受体的唯一组分，因为表达人CD 4分子的小鼠细胞不被HIV感染。我们最近在人类T4^+淋巴细胞中发现了一种新的膜结合丝氨酸蛋白酶，命名为类胰蛋白酶TL 2，它与HIV gp 120的V3结构域特异性结合，而不是与CD 4受体结合。据报道，V3结构域是HIV的主要中和决定因素，也是HIV感染细胞嗜性的决定因素。Scatchard分析揭示了类胰蛋白酶TL 2上的单一类型的gp 120结合位点，其对类胰蛋白酶TL 2的表观解离常数为3.8 × 10 - 4 μ M。为了找到有效抑制gp 120与类胰蛋白酶TL 2结合的化合物，我们分析了在其活性位点具有序列GPCR的各种Kunitz型蛋白酶抑制剂和在其中心具有序列GPCR的合成V3结构域肽的作用<-8>，其对应于各种HIV株的gp 120和抗类胰蛋白酶TL 2的抗体的主要中和表位。结果表明，胰蛋白酶抑制剂、Kunitz型蛋白酶抑制剂和针对类胰蛋白酶TL 2的抗体有效地抑制了gp 120与类胰蛋白酶TL 2的结合。它们还抑制HIV诱导的合胞体形成。虽然V3结构域是一个高变区，但类胰蛋白酶TL 2可能是不同HIV毒株V3结构域在T淋巴细胞膜上的共同结合受体。这些结果表明，类胰蛋白酶抑制剂和抗类胰蛋白酶TL 2的抗体可能是有用的治疗艾滋病的治疗。胰蛋白酶抑制素基因的克隆及其在大肠杆菌中表达的研究。大肠杆菌正在进行中。这些化合物在体内和体外抗HIV感染的作用有待进一步研究

Infection by human immunodeficiency virus (HIV) is due to virus-cell fusion mediated by interaction of the envelope glycoprotein gp120 of HIV with the CD4 molecule present on the surface of T4^+ lymphocytes. However, the CD4 molecule may not be the only component of HIV receptor because mouse cells expressing the human CD4 molecule are not infected by HIV. We recently found a novel membrane-bound serine protease, named tryptase TL2, other than CD4 receptor in human T4^+ lymphocytes which specifically binds V3 domain of HIV gp120. The V3 domain has been reported to be the principal neutralizing determinant of HIV and also to be a determinant for cellular tropism of HIV infection. Scatchard analysis revealed a single class of gp120 binding site on tryptase TL2 with an apparent dissociation constant of 3.8 x 10^<-8> M for tryptase TL2.In order to find the compound(s) which effectively inhibit the binding of gp120 to tryptase TL2, we have analyzed the effect of various Kunitztype protease inhibitors with the sequence GPCR in their active site and synthetic V3 domain peptides with the sequence GPCR in their center, which correspond to the principal neutralizing epitopes of gp120 of various HIV strains and of antibody against tryptase TL2. The results show that trypstatin, Kunitz type protease inhibitor, and antibody against tryptase TL2 effectively inhibited the binding of gp120 to tryptase TL2. They also inhibited syncytia formation induced by HIV. Although V3 domain is a hypervariable region, tryptase TL2 may be a common binding receptor in the membrane of T lymphocytes for various V3 domain of HIV strains. These results suggest that trypstatin and the antibody against tryptase TL2 may be useful for therapeutic treatment for AIDS. The studies on DNA cloning of trypstatin and its expression in E. Coli are now in progress. Further studies are need to confirm the effect of these compounds on HIV infection in vivo and in vitro