Detection of Rh D-associated epitopes in human and animal tissues using human monoclonal anti-D antibodies.

The distribution of Rh D-associated epitopes in human and animal tissues has been assessed by immunochemical techniques using six human monoclonal anti-D antibodies. The IgM antibody MAD-2 reacted predominantly with endothelial cells lining blood vessels and with animal leucocytes and human leucocytes from both Rh D-positive and Rh D-negative donors. Immunoblotting revealed reactivity with a 55 kDa tissue component which was most prominent in homogenates of heart, lung and spleen. In contrast, the IgG antibodies UCHD4 and FOG-1 stained smooth muscle, and UCHD4 in addition weakly stained cardiac and skeletal muscle and the glomeruli of kidney. Immunoblotting with UCHD4 revealed reactivity with a 27 kDa tissue component which was most prominent in heart homogenates. The results show that the six monoclonal anti-D antibodies recognize at least four different epitopes and that Rh D-associated epitopes may occur in non-erythroid cell types.