Meeting Abstract

P3.197  Tuesday, Jan. 6  Seasonal variation in innate and adaptive immunity of adult red-eared sliders, Trachemys scripta ZIMMERMAN, L.M.*; PAITZ, R.T.; VOGEL, L.A.; BOWDEN, R.M.; Illinois St. Univ.; Illinois St. Univ.; Illinois St. Univ.; Illinois St. Univ. lmzimme@ilstu.edu

Previous studies on the reptile immune system have shown that aspects of the innate and adaptive immune response exhibit seasonal variation that is species specific. Sex may play a role in seasonal variation in red-eared slider turtles Trachemys scripta, as male and females have different patterns of resource allocation across the seasons. The purpose of this study was to examine the effects of season on various branches of the immune system of adult red-eared sliders. Blood samples were taken from male and female turtles during the active season which occurs from late April until October. A bactericidal assay that measures the killing capacity of plasma against bacteria was used to measure innate immunity. A delayed type hypersensitivity (DTH) reaction to phytohemagglutin (PHA) was used to measure cell-mediated immunity. Total immunoglobulin levels will be determined by ELISA as a measure of humoral immunity. Results indicate a significant effect of season on both killing capacity and the DTH response. Killing capacity peaked in late May and continued into early June before dropping off dramatically in August and September. The DTH response peaked in late May before dropping off to a consistent level for the remainder of the active season. There was no significant correlation between an individuals killing capacity and the DTH response. No significant effect of sex on the killing capacity and the DTH response was found, therefore differences in resource allocation between the sexes are most likely not driving the observed seasonal variation in immune function. Our results suggest that there is a complex relationship where the change in season affects each branch of the immune system differently.