Expression of mouse and human TIGIT on follicular T helper cells and other lymphocytes (152.10)

Abstract

Abstract T cell immunoreceptor with Ig and ITIM domains (TIGIT) is a newly identified member of the polio virus receptor family. In humans, its expression has been reported on NK cells, regulatory T cells (Treg), memory CD4 T cells, follicular T helper cells (Tfh), and CD8 T cells, but not on B cells or naïve CD4 T cells. In mice, mRNA for TIGIT has been observed in Tfh but not naïve T cells. We examined the expression of TIGIT on lymphocytes in mice and humans using two novel antibodies, clone GIGD7 and MBSA43, respectively. We found that the expression patterns on unstimulated lymphocytes were dissimilar between mice and humans, whereas expression following activation was more consistent. For the first time, we show that TIGIT is expressed on the surface of mouse Tfh, consistent with studies examining mRNA and similar to previous observations in humans. Finally, the response of memory T cells in vitro was slightly increased when normal human peripheral blood cells were stimulated in the presence of MBSA43 to block TIGIT, consistent with its role as an inhibitory receptor. These two antibodies will facilitate the characterization of TIGIT on Tfh and Treg, as well as human memory T cells and NK cells and will help to elucidate the role of this inhibitory receptor during immune responses.