Histamine receptor H1 (H1R) is a susceptibility gene in both experimental autoimmune encephalomyelitis (EAE) and experimental autoimmune orchitis (EAO), 2 classical T cell–mediated models of organ-specific autoimmune disease. Here we showed that expression of H1R in naive CD4+ T cells was required for maximal IFN-γ production but was dispensable for proliferation. Moreover, H1R signaling at the time of TCR ligation was required for activation of p38 MAPK, a known regulator of IFN-γ expression. Importantly, selective reexpression of H1R in CD4+ T cells fully complemented both the IFN-γ production and the EAE susceptibility of H1R-deficient mice. These data suggest that the presence of H1R in CD4+ T cells and its interaction with histamine regulates early TCR signals that lead to Th1 differentiation and autoimmune disease.
Rajkumar Noubade, Graeme Milligan, James F. Zachary, Elizabeth P. Blankenhorn, Roxana del Rio, Mercedes Rincon, Cory Teuscher