The Reaction of Zymosan with the Properdin System: Isolation of Purified Factor D from Guinea Pig Serum and Study of Its Reaction Characteristics

作者：Volker Brade, Anne Nicholson, Gerald D. Lee, Manfred M. Mayer · 发表于：The Journal of Immunology · 年份：1974 · DOI：10.4049/jimmunol.112.5.1845 · 被引用次数：41 · 研究领域：Venomous Animal Envenomation and Studies、Lipid Membrane Structure and Behavior、Ion channel regulation and function

Abstract On incubation with serum, zymosan (Z) combines with several serum components, collectively designated X, to form an intermediate, ZX, which activates the complement system by cleavage of components C3 and C5. The enzymes, responsible for cleaving C3 and C5 differ from C̄4̄,2̄ and C̄4̄,2̄,3̄, and are collectively designated “properdin enzymes.” In our earlier studies it was shown that these are multi-unit complexes comprising factor B and complement fragment C3b. The present experiments extend our work on the C3-cleaving properdin enzyme with respect to a third component, designated factor D. On extended incubation at 37°C and long storage at 0°C, ZX changes to a severely decayed precursor, designated ZXd2, due to loss of factors B and D. if fresh factor B is supplied, ZXd2 can serve as a reagent for the detection and measurement of D. This method is far more sensitive than assaying with factor B and the cobra venom factor. Rigorous evidence is presented in the present work that the factor detected by each of these assay systems is one and the same despite the large difference in sensitivity. A procedure is described for isolation of D from guinea pig serum in a highly purified state as judged by disc electrophoresis on polyacrylamide gel. The final product was found to have a molecular weight of about 22,000 daltons, and a frictional coefficient, f/fo, of about 1.1, as estimated from its sedimentation rate of ca. 2.6S, its diffusion coefficient of ca. 10.5 × 10-7 cm2...