Meeting Abstract

P2.37  Wednesday, Jan. 5  Age-related changes in antibodies of the red-eared slider, Trachemys scripta ZIMMERMAN, L.M.*; VOGEL, L.A.; BOWDEN, R.M.; Illinois State Univ.; Illinois State Univ.; Illinois State Univ. lmzimme@ilstu.edu

In humans, specific antibody responses decrease with age while natural antibodies (NAbs) increase. This reduction in specific antibody responses has been viewed as a contributor to the increase of mortality and morbidity with increasing age. Like humans, reptiles show an age-specific increase in NAbs, but unlike humans, reptiles of all ages have a less robust specific antibody response. Consequently, NAbs are viewed as a key component of immune defense in reptiles. Given the comparatively lesser reliance on the specific antibody response in reptiles, the age-specific increase in NAbs may constitute an improvement in immune defense. However, little is known about the quality of antibodies produced with age in reptiles. In order to investigate this, blood samples were taken from male and female adult red-eared slider turtles, Trachemys scripta, throughout the active season. Because red-eared sliders grow throughout their lifetime, plastron length was measured as a proxy for age. Affinity of antibodies to lipopolysaccharides (LPS), an antigen likely encountered by turtles, and keyhole limpet hemocyanin (KLH), a novel antigen, was determined using a competitive ELISA. Preliminary results suggest that affinity to either antigen did not vary seasonally or with sex. Affinity to LPS increased with age while affinity to KLH did not. This suggests that while affinity may not improve in the short term with immunization, affinity may improve with repeated exposure over time. Therefore, in reptiles, unlike in humans, changes in humoral responses may not cause impairment in immune defense with age.