T2-MZP Bregs from WT and Jα18−/− mice (T2-MZP Bregs express CD1d in both strains) suppressed arthritis and significantly inhibited the frequency of IFN-γ+CD4+ T cells in WT recipient mice (p < 0.01 by one-way ANOVA) (Fig. 6c, d). The gene discussed is CD4; the disease is arthritic joint disease.