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

PABLO A. SIROSKI, MARK E. MERCHANT, VIRGINIA PARACHU MARCO, CARLOS PINIA AND HUGO H. ORTEGA

ZOOLOGICAL STUDIES

ACAD SINICA INST ZOOLOGY

Lugar: Taipei, Taiwan; Año: 2010 vol. 49 p. 64 - 70

1021-5506

The sheep  red blood cell  (SRBC) hemolysis assay was used to detect and characterize complement-system activity of broad-snouted caiman  (Caiman  latirostris) serum. The hemolytic activity of caiman serum was  inhibited by 2 classic  inhibitors  (EDTA and heat) suggesting  the existence of complement-system activity.  In addition, we found that the capacity of C. latirostris serum to disrupt SRBCs was concentration,  temperature, and kinetics dependent.   Hemolytic activity was detected  from a very low concentration (< 10%) of caiman serum and  increased until 100%.   Temperature  infuenced  the activity of the serum by disrupting SRBC membranes.   The serum showed a peak of hemolysis between 30 and 40°C, within which  lies  the optimal  temperature caimans prefer during  thermoregulation  for normal physiological processes.  Hemolytic activity rapidly occurred at 2 min, and maximum activity was detected at 60 min.  These observations  reflect previously  reported  findings  in other crocodilian species  (Alligator mississippiensis, Crocodylus johnstoni, and Cro. porosus), thus adding to the knowledge of the role of the complement system in immunological activities of crocodilians.