Differential expression of regulator of G-protein signalling transcripts and in vivo migration of CD4+ naïve and regulatory T cells.

The immune response of T lymphocytes to pathogens is initiated in draining secondary lymphoid organs, and activated cells then migrate to the site of infection. Thus, control of naive and regulatory CD4+ T-cell migration is crucial; however, it is poorly understood in physiological and pathological conditions. We found that CD4+ subpopulations displayed characteristic regulator of G-protein signalling (RGS) gene expression profiles. Regulatory T cells express higher levels of RGS1, RGS9 and RGS16 than naive cells. These genes are up-regulated upon cell activation and their level of expression correlates with in vivo cell migration. Using parabiosis, we showed that regulatory T lymphocytes migrate less than naive T cells and that migrant naive T cells express even lower RGS levels than their static counterparts. Our results show an inverse correlation between the capacity to migrate and the levels of RGS1, RGS9 and RGS16 for both naive and regulatory T cells. Taken together, these results suggest a role for RGS molecules in chemokine-induced lymphocyte migration and demonstrate the peculiarity of regulatory T cells in terms of phenotype and migration ability, providing new insights into their function.