Meeting Abstract
Stress is known to have far-reaching effects on vertebrate immune defenses; however, it remains unclear to what extent stress hormones, such as corticosterone (CORT), influence different components of immune defense in larval amphibians. The purpose of this study was to identify whether exogenous CORT has an effect on innate and acquired immunity of Northern Leopard Frog tadpoles, Lithobates pipiens, when exposed to an opportunistic pathogen, Aeromonas hydrophila. We hypothesized that by elevating CORT, the tadpole immune defenses would be altered. In order to test innate and acquired immunity within the tadpoles, we conducted two experiments. In the first experiment, we exposed one group to exogenous CORT and maintained a control group without exogenous CORT, with neither exposed to A. hydrophila. In the second experiment, we exposed all tadpoles to A. hydophila, but again only exposed one group to exogenous CORT. We used a bacteria killing assay to assess innate immunity and an A. hydrophila ELISA to measure IgM and IgY antibodies generated in an acquired immune response. We found that the CORT dosed tadpoles killed significantly more A. hydrophila than the control tadpoles. Conversely, tadpoles dosed with CORT for an extended period of time had significantly lower plasma IgM and IgY against A. hydrophila. Our findings suggest that stress has differential effects on innate and acquired immunity in larval Northern Leopard Frogs similar to that seen in adult frogs.
