Katz Y, Strunk R C
Pulmonary Division, St. Louis Children's Hospital, MO 63110.
J Immunol. 1988 Jul 15;141(2):559-63.
The alternative pathway of C activation is Ag-independent and forms a first line of defense against infection before immune response. The C3 convertase, C3bBb, formed during activation of the alternative pathway is tightly regulated, with destabilization produced by factor H. Using metabolic labeling with [35S]methionine, immunoprecipitation, and SDS-PAGE, we demonstrated that human skin fibroblasts synthesized and secreted factor H protein. Two forms of the protein were identified, the approximately 160-kDa form seen more prominently in serum and a 45-kDa form that has also been identified in serum. The cells contained two forms of factor H mRNA, 4.4 and 1.8 kb. IFN-gamma increased factor H protein synthesis and mRNA content. No effect was observed with LPS. Neither HepG2 cells or human peripheral blood monocytes synthesized factor H protein or contained factor H mRNA.
补体C激活的替代途径不依赖抗体，在免疫反应之前形成抗感染的第一道防线。在替代途径激活过程中形成的C3转化酶C3bBb受到严格调控，因子H可使其失稳。我们通过[35S]甲硫氨酸代谢标记、免疫沉淀和SDS-PAGE证明，人皮肤成纤维细胞合成并分泌因子H蛋白。鉴定出该蛋白的两种形式，约160 kDa的形式在血清中更显著，还有一种45 kDa的形式也在血清中被鉴定出。细胞含有两种形式的因子H mRNA，分别为4.4 kb和1.8 kb。干扰素-γ增加因子H蛋白的合成及mRNA含量。脂多糖未产生影响。HepG2细胞和人外周血单核细胞既不合成因子H蛋白，也不含有因子H mRNA。
