To determine whether the phenotypes of Mb1creHif1af/f mice in autoimmune diseases, including the observed exacerbated pro-inflammatory T cell response, were secondary to a defect in IL-10 production by B cells, naïve CD4 T cells were co-cultured with CD1dhiCD5+ B cells from WT mice in presence or absence of anti-IL-10 antibody. Here, CD4 is linked to autoimmune disease.