Rapid and Inexpensive Method for the Spectroscopic Determination of Innate Immune Activity of Crocodilians

Abstract

We have employed a spectroscopic assay based on the hemolysis of sheep red blood cells (SRBCs) to assess the immune system of the American alligator (Alligator mississippiensis). The assay is based on the hemolytic disruption of the SRBCs by the immunological proteins in the crocodilian serum. Incubation of 1% SRBCs (v/v) with alligator serum resulted in hemolysis that was measured at 540 nm in a microtiter plate reader. The hemolysis was concentration‐, time‐, and temperature‐dependent. This assay is rapid, inexpensive, easy to perform, requires small sample volumes, and is useful for evaluating the humoral immune response of crocodilians.

Keywords:

• Crocodilian
• hemoglobin
• humoral immunity
• innate immunity
• serum complement
• spectrophotometry

Acknowledgments

The authors wish to thank Dr. Michael Berger, Wildlife Division Director of the Texas Parks and Wildlife Department, for access to public lands on which to capture wild alligators. This grant was supported by a Merck/AAAS undergraduate science research program award.