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Isolation of Intermediates and Sequential Analysis of the Properdin System: The Role of Factor B

1973; American Association of Immunologists; Volume: 111; Issue: 1 Linguagem: Inglês

10.4049/jimmunol.111.1.287.b

1550-6606

Volker Brade, Gerald Lee, Anne Nicholson, Manfred M. Mayer,

Blood disorders and treatments

Abstract On incubation with guinea pig serum zymosan (Z) combines with several factors (X) to form an intermediate complex (ZX), which is capable of inactivating purified C components C3 or C5 by cleavage. ZX formation increases with time of incubation and then declines due to a decay process. The Tmax times at 17°C, 27°C, and 37°C are 4 min, 2 min, and 1 min, respectively, for C3 cleavage by ZX. For C5 cleavage Tmax at 27°C and 37°C is 5 min and 2 min, respectively. ZX generation with C4-deficient guinea pig serum is slower than in normal guinea pig serum, which suggests that the classical pathway may accelerate the generation of ZX. On reaction of Z with guinea pig serum, factor B activity is consumed. This is due, at least in part, to uptake of factor B by Z, as demonstrated by the fact that antibody to factor B inhibits C3 and C5 cleavage by ZX.