Characterization of Serum Complement Activity of Broad-Snouted Caiman (Caiman latirostris, Crocodilia: Alligatoridae)

SIROSKI, P.; MERCHANT M.; PARACHÚ MARCÓ M.V.; PIÑA, C.I.; HORTEGA, H.H.

ZOOLOGICAL STUDIES

Academia Sinica

Año: 2009 vol. 49 p. 64 - 70

1021-5506

The sheep red blood cell (SRBC) hemolysis assay was developed to detect complement systemactivity. Based on this technique, we detected and characterized the complement system activityof broad-snouted caiman (Caiman latirostris) serum. Hemolytic activity of caiman serum wasinhibited by 2 classical inhibitors (EDTA and heat) suggesting that the ability of C. latirostrisserum could be attributed to a complement system activity. We found that capacity of C.latirostris serum to disrupt SRBCs is concentration-, temperature-, and kinetics-dependent.Hemolytic activity was detected at very low concentration (<5%) increasing until 50% of caimanserum. Temperature influenced the activity of the serum to disorder the SRBCs membranes;serum showed a peak of hemolysis at 35ºC, very close to barely higher than the optimaltemperature crocodilians prefer during thermoregulation for normal physiological processes. Thehemolytic activity occurred rapidly at 2 min and maximum activity was detected at 60 min.These observations, measured as an immune response, could be one of the reasons of the highresistance crocodilians showed to microbial infection. We found that mechanisms of complementactivities for diverse crocodilian species studied are similar. The foregoing data highlight thesignificant contribution of the complement system to the immunological activities ofcrocodilians.