MARTIN, LB*; WEIL, ZM; NELSON, RJ; The Ohio State University; The Ohio State University; The Ohio State University: The immune defenses of rodents: model systems for bridging conservation, medicine, and ecophysiology.

The control of disease in humans and other species has been improved greatly through study of the molecular and cellular processes underlying immune responses. Recent ecological approaches to studying the vertebrate immune system have provided insight, however, into why immune defenses often vary among and within species. Here, we discuss the results of two eco-immunological studies on rodents from our lab. In the first study, we investigated the effects of trenbolone, a growth promoter of cattle, on wound healing, antibody production to a novel antigen, and ex vivo bacterial killing in house mice. Because trenbolone has androgenic properties, we expected it would suppress components of immune activity like endogenous androgens sometimes do. In our study, trenbolone retarded wound healing in mice to a similar degree as exogenous testosterone; bacterial killing and antibody production assays are in progress. In the second study, we asked whether the different paces of reproductive life of six species of Peromyscus mice influence the architecture of their immune systems. We expected that species that reproduce prolifically would invest in cheaper immune defenses than more reproductively conservative species, leading their immune systems to be biased to developmentally cheaper, non-specific defenses overall. This hypothesis was generally supported: in smaller, reproductively prolific species, bacterial killing capacity was stronger, but primary and secondary antibody responses to a novel antigen were weaker and rates of wound healing were slower relative to larger, less prolific species. Altogether, these studies indicate that adaptationist approaches to understanding the vertebrate immune system may improve human health and conservation efforts.