Anti-C3a, Anti-C3B (Anti-B) and Their Reaction with the Anaphylatoxic Fragment C3a

Abstract

Specific antisera against the third human complement component (C3) and its fragments (C3a, C3c and C3d) were raised in rabbits. The reactions of anti-C3B (anti-B) with the anaphylatoxic fragment C3a were investigated by means of line electrophoresis, agglutination inhibition and Prausnitz-Küstner type reactions. C3a could not absorb anti-C3B antibodies, so C3B (B) determinants could not have been present on C3a and anti-C3a is not identical to anti-C3B. Anti-C3B antibodies did not react with the fragments C3a, C3b, C3c or C3d. Only with native C3 and activated C3 on the erythrocyte surface were reactions demonstrable.