Loss of T cells influences sex differences in behavior and brain structure

Clinical and animal studies demonstrate that immune-brain communication influences behavior and brain function. Mice lacking T cell receptor beta and delta chains were tested in the elevated plus maze, open field, and light-dark test and showed reduced anxiety-like behavior compared to wild type. Interestingly sex differences were observed in the behavioural phenotype of TCR beta-/-delta- mice. Specifically, female TCR beta-/-delta- mice spent more time in the light chamber compared to wild type females, whereas male TCR beta-/-delta- spent more time in the center of the open field compared to wild type males. In addition, TCR beta-/-delta- mice did not show sex differences in activity-related behaviors observed in WT mice. Ex vivo brain imaging (7 Tesla MRI) revealed volume changes in hippocampus, hypothalamus, amygdala, peri-aqueductal gray, and dorsal raphe and other brain regions between wild type and T cell receptor knockout mice. There was also a loss of sexual dimorphism in brain volume in the bed nucleus of the stria terminalis, normally the most sexually dimorphic region in the brain, in immune compromised mice. These data demonstrate the presence of T cells is important in the development of sex differences in CNS circuitry and behavior. (C) 2015 Elsevier Inc. All rights reserved.