When an antihuman BMP antibody is administered to an immortalized human mesangial cell line having been cultured in the presence of human BMP, the antihuman BMP antibody strongly inhibits the production of type IV collagen by the mesangial cells. Since multiple signal transducing pathways participate in the abnormal proliferation of type IV collagen, it has been completely impossible to anticipate whether or not the abnormal proliferation of type IV collagen can be inhibited in practice by blocking the BMP signal. However, the above finding has clarified for the first time that the antihuman BMP antibody is highly effective in inhibiting the abnormal proliferation of type IV collagen. Therefore, the antihuman BMP antibody is usable as a novel remedy for a renal disease in which the abnormal proliferation of mesangial matrix participates.
