Complement profiles in monkeys subjected to aggregate (immune complex) anaphylaxis, and following injection of...

Complement profiles were established in four groups of Macaca irus monkeys: (I) Aggregate (immune complex) anaphylaxis was induced following immunization, with ovalbumin. Upon challenge, systemic arterial pressure decreased from 115 to 50 mm Hg (mean values) in 10 min. The complement profiles revealed decreases in: C1q to less than 10% of initial value within 5 min; C4 proportional to hypotension; C3 slowly to 60% at 24 h; C5, C6, C7, C8 and factor B to about 80% of initial value in 5--30 min. Conversion products of C3 and factor B were detected on the day of anaphylaxis. In conclusion, mainly the classical and to a lesser extent the alternative pathway, were activated. Following injection of (II) native B 512 dextran, (III) biodegradable starch microspheres, and (IV) saline, no significant changes of complement profiles were seen. Conversion products of C3 and factor B were, however, demonstrable in groups II and III without appearance of clinical signs.