Open AccessAn Alternate Complement Pathway: C-3 Cleaving Activity, Not Due to [unk], on Endotoxic Lipopolysaccharide after Treatment with Guinea Pig Serum; Relation to Properdin
Author(s) -
Robert L. Marcus,
Hyunjung Shin,
Manfred M. Mayer
Publication year - 1971
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.68.6.1351
Subject(s) - properdin , lipopolysaccharide , guinea pig , incubation , alternative complement pathway , cleavage (geology) , chemistry , biology , complement factor b , complement system , microbiology and biotechnology , antibody , biochemistry , immunology , endocrinology , paleontology , fracture (geology)
The reaction between endotoxic lipopolysaccharide (LPS) and the guinea pig complement system was shown to proceed by way of an intermediate complex, LPS-X, which contains at least six guinea pig serum proteins. LPS-X, like [unk] (sheep erythrocytes carrying antibody molecules and [unk] complexes), destroys the C3 molecule by cleavage. On incubation at 37°C, LPS-X loses its capacity to destroy C3 at about the same rate as the decay of [unk], so that it has been assumed that LPS-X carries [unk] sites that are responsible for the destruction of C3. We have now shown that monospecific rabbit antiguinea pig C2, which effectively inhibits C3 cleavage by [unk], does not interfere with the destruction of C3 by LPS-X. Furthermore, not more than a trace of C2ad is released from LPS-X on incubation at 37°C. These results indicate that LPS-X does not carry a significant quantity of [unk] and, hence, that its capacity to destroy C3 is due to another factor which is presumably a component of the properdin system.