Therefore, in the present study, we have investigated the roles of NKT cells in lupus nephritis using BWF1 mice. We show that the repeated administration of α-GalCer into BWF1 mice induced beneficial effects, as follows: (i) it improved proteinuria which represents a hallmark of renal injury, by protecting nephrin, a key functional molecule in the slit diaphragm of the podocytes21; (ii) it suppressed B cell function and decreased glomerular immune complex deposits; (iii) it induced not only an anergic state to α-GalCer in NKT cells, but also decreased the number of NKT cells in multiple organs and the production of IL-4 by these cells.