Sadlon T A, Parker S J, Gordon D L
Department of Microbiology and Infectious Diseases, Flinders Medical Centre, Bedford Park, Australia.
Immunol Cell Biol. 1994 Dec;72(6):461-70. doi: 10.1038/icb.1994.70.
We investigated complement activation by recombinant gp120 (rgp120) treated CD4 cells and the role host complement regulatory proteins play in controlling C3 deposition. Complement activation was determined by detection of C3 on rgp120 coated cells in the presence and absence of HIV seropositive sera using flow cytometry. Treatment of rgp120 coated cells with complement resulted in C3 deposition only if HIV positive sera was included. Examination of C3 fragments on these cells demonstrated rapid cleavage of C3b to iC3b. The role of the regulatory proteins was examined by pretreating cells with mAb to block decay accelerating factor (DAF) or membrane cofactor protein (MCP) or by using factor H depleted sera as a complement source. Inhibition of DAF or use of factor H depleted sera significantly increased C3 deposition on rgp120 coated cells. In contrast, C3 deposition on rgp120 coated cells was not increased after blocking MCP. The sensitivity of rgp120 coated cells to complement lysis was unchanged after inhibition of the regulatory proteins, despite the increase in C3 deposited. These results indicate that in a model of virus infected cells, C3 deposition is regulated by DAF and factor H but MCP appears to have no role.
我们研究了重组gp120（rgp120）处理的CD4细胞引发的补体激活，以及宿主补体调节蛋白在控制C3沉积中所起的作用。通过使用流式细胞术检测存在和不存在HIV血清阳性血清时rgp120包被细胞上的C3来确定补体激活。仅当包含HIV阳性血清时，用补体处理rgp120包被的细胞才会导致C3沉积。对这些细胞上的C3片段进行检测表明，C3b迅速裂解为iC3b。通过用单克隆抗体预处理细胞以阻断衰变加速因子（DAF）或膜辅因子蛋白（MCP），或使用因子H缺陷血清作为补体来源来研究调节蛋白的作用。抑制DAF或使用因子H缺陷血清会显著增加rgp120包被细胞上的C3沉积。相比之下，阻断MCP后，rgp120包被细胞上的C3沉积并未增加。尽管C3沉积增加，但抑制调节蛋白后，rgp120包被细胞对补体裂解的敏感性并未改变。这些结果表明，在病毒感染细胞模型中，C3沉积受DAF和因子H调节，但MCP似乎不起作用。
