Pugliese A, Savarino A, Cantamessa C, Torre D
Department of Medical and Surgical Sciences, University of Turin, Italy.
Cell Biochem Funct. 1996 Dec;14(4):291-6. doi: 10.1002/cbf.693.
We have previously demonstrated that fibronectin (FN) can bind HIV-1 envelope proteins, in particular gp 120. The aim of the present study was to determine some biological effects of this phenomenon. Pretreating HIV-1 with human FN increased the infectivity of HIV-1, when a low concentration of the virus was used. In contrast, an RGD-containing pentapeptide (Gly-Arg-Gly-Asp-Ser), which is a fundamental binding site of FN, reduced the infectivity of a suspension of HIV-1 at high concentrations of the virus. It is likely that FN bridges the cell surface and the virions, while the RGD-containing pentapeptide may saturate the HIV-1 binding sites for cell surface receptors. Moreover, gp 120 was bound to the FN present on the surface of platelets. The specificity of this binding was confirmed by the inhibition obtained by pretreating platelets with anti-FN antibodies. The consequence of the surface modifications of the platelets could explain the thrombocytopenia that frequently occurs in patients infected with HIV and suggests also the possibility that platelets could be a vehicle for the virus in the circulation.
我们之前已经证明，纤连蛋白（FN）能够结合HIV-1包膜蛋白，尤其是gp120。本研究的目的是确定这一现象的一些生物学效应。当使用低浓度病毒时，用人FN预处理HIV-1可增加其感染性。相反，一种含RGD的五肽（甘氨酸-精氨酸-甘氨酸-天冬氨酸-丝氨酸），它是FN的一个基本结合位点，在高浓度病毒时可降低HIV-1悬浮液的感染性。很可能FN在细胞表面和病毒粒子之间形成桥梁，而含RGD的五肽可能会饱和HIV-1细胞表面受体的结合位点。此外，gp120与血小板表面存在的FN结合。用抗FN抗体预处理血小板所获得的抑制作用证实了这种结合的特异性。血小板表面修饰的后果可以解释感染HIV的患者中经常出现的血小板减少症，也提示了血小板可能是循环中病毒载体的可能性。
