SPECIFIC MONOCLONAL-ANTIBODIES AGAINST LEUKOCYTE-RESTRICTED CELL-SURFACE MOLECULE CD43 REACT WITH NONHEMATOPOIETIC TUMOR-CELLS

CD43 is the major sialoglycoprotein found on the surface of cells of h emopoietic origin. Because CD43 is a typical member of the surface muc ins, molecules that play a relevant role in tumor progression, we have addressed the expression of CD43 in nonhematopoietic tumor cells. For this purpose, we have tested a broad panel of anti-CD43 antibodies on tumors of different embryonic origins. Of the 17 anti-CD43 mAbs used, 9 reacted with leukocytes in paraffin-fixed formalin-embedded lymph n ode tissues. Two mAbs, BS1 and L10, stained 24 out of 31 (78%) nonhema topoietic tumors analyzed; i.e., some tumors were positive for both an tibodies, and others were positive for either L10 or BS1. We have also found reactivity of these two anti-CD43 mAbs in 13 out of 20 metastas es studied.