The binding of nascent human C3b (i.e. the fragment of C3 just after trypsin cleavage) to mouse peritoneal macrophages was demonstrated by immune adherence. Acceptor-bound C3b could be detected longer than 24 h on the cell membrane. The rosette formation and phagocytosis of SRBC coated with anti-SRBC rat IgG was inhibited by preincubation of the cells with C3 and trypsin (15 min, 37°C). However, the phagocytosis of opsonized yeast particles was not influenced by acceptor-bound C3b, proving that C3bC3b acceptor interaction did not alter the function of C3b-receptors. Acceptor-bound C3b on the macrophages failed to mediate phagocytosis of human 0,Rh+ red cells having C3b-receptors.
- C3b acceptor FcγR-inhibition - peritoneal exudate cells immune adherence
ASJC Scopus subject areas
- Immunology and Allergy