Anti-proliferative effects of CP690,550 on CD3 Ab activated CD4+ T cells. CD4+ T cells were stimulated with CD3 monoclonal antibodies in the presence or absence of CP690,550. After 48-hr, proliferation was determined by the XTT assay. * p = 0.023 vs CD3 Ab-stimulated lymphocytes. ** p = 0.010 vs CD3 Ab-stimulated lymphocytes. The results are expressed as the mean ± SD of two independent experiments.