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

SIROSKI, PABLO; MERCHANT, MARK; PARACHÚ MARCÓ M.V.; PIÑA, C.I.; ORTEGA, HUGO

ZOOLOGICAL STUDIES

Elsevier

Lugar: Masachusstes, USA; Año: 2008

1021-5506

The sheep red blood cell (SRBC) hemolysis assay was developed to detect complement system activity. Based on this technique, we detected and characterized the complement system activity of broad-snouted caiman (Caiman latirostris) serum. Hemolytic activity of caiman serum was inhibited by 2 classical inhibitors (EDTA and heat) suggesting that the ability of C. latirostris serum 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 caiman serum. Temperature influenced in the activity of the serum to disorder the SRBCs membranes; serum showed a peak of hemolysis at 35ºC, very close to the optimal temperature crocodilians prefer during thermoregulation for normal physiological processes. The hemolytic activity occurred rapidly at 2 min and maximum activity was detected at 60 min.These observations, measuredas an immune response, could be one of the reasons of the high resistance crocodilians showed to microbial infection. We found that mechanisms of complement activities for diverse crocodilian species studied are similar. The foregoing data highlight the significant contribution of the complement system to the immunological activities of crocodilians.Keywords: Crocodilians, ectothermics, hemolytic assays, immunology, innate immunity.