Identification and characterization of serum complement activity in the American crocodile (Crocodylus acutus).
Incubation of unsensitized sheep red blood cells with serum from the American crocodile (Crocodylus acutus) resulted in a concentration-dependent hemolysis. The hemolytic activity was heat-sensitive, and inhibited by EDTA in a concentration-dependent manner. The EDTA-inhibited SRBC hemolysis could be restored by the addition of excess Ca2+ or Mg2+, but not Ba2+ or Cu2+, revealing the specificity of this activity for these two divalent cations. The hemolytic activity of crocodile serum was titer-dependent, with 329 microL producing 50% of maximal SRBC hemolysis. The complement activity was also temperature-dependent, with decreased activity at lower temperatures (5-15 degrees C) and maximal activity occurred at 30-40 degrees C. The hemolysis occurred relatively slowly, with near zero activity after 10 min, 40% of activity observed within 15 min of exposure to SRBCs, and maximal activity at 30 min.
Merchant
Mark
M
Department of Chemistry, McNeese State University, Lake Charles 70609, LA, USA. mmerchant@mcneese.edu
McFatter
Justin
J
Mead
Stephanie
S
McAdon
Charles
C
Wasilewski
Joe
J
D000489:Alligators and Crocodiles / Q000097:blood* / Q000276:immunology*; D000818:Animals; D002413:Cations, Divalent / Q000494:pharmacology; D003170:Complement Pathway, Alternative; D003165:Complement System Proteins / Q000378:metabolism*; D004492:Edetic Acid / Q000494:pharmacology; D006461:Hemolysis / Q000187:drug effects; D066298:In Vitro Techniques; D012756:Sheep
D002413:Cations, Divalent; D003165:Complement System Proteins; D004492:Edetic Acid