T cell dependent & independent behavioral phenotypes in Rag2-/- mice

Abstract

The Rag2-/- mouse model of T cell deficiency is a useful tool for the study of behaviors associated with T cell function. We have previously shown that Rag2-/- mice on a BALB/c background are more resistant to developing post-traumatic anxiety using the model of exposure to predator odor (POE). The objectives of the present studies were two-fold: first, to determine if behavioral differences in the POE model were also present in Rag2-/- mice on a C57Bl/6 background and second, to determine if these behavioral differences were dependent on T cells. Wild type (WT) and Rag2-/- mice on C57Bl/6 background and Rag2-/- mice reconstituted with naive T cells were compared in the POE model. Mice were exposed to cat odor for 10 minutes and tested 7 days later in the elevated plus maze (EPM) test followed by the acoustic startle response (ASR) one day later. Compared to mice on a BALB/c background, WT and Rag2-/- mice showed consistent behavioral phenotypes in the EPM and ASR, with Rag2-/- mice displaying decreased ASR reactivity with respect to WT and no differences in the EPM. Reconstitution with T cells modified behavioral responses in the EPM, but did not affect ASR responses. These results suggest that T cells may affect stress responsiveness, independent of genotype, by functional as well as developmental effects in an endophenotype-specific manner.