Characterization of Wue-1, a novel monoclonal antibody that stimulates thegrowth of plasmacytoma cell lines

A new monoclonal antibody, Wue-1, which specifically recognizes normal and malignant plasma cells, is characterized. Biochemical studies showed that m onoclonal antibodies (mAbs) recognize a protein of 94 kDa. Using triple-sta ining flow cytometry and double-labeling immunohistochemical techniques, tw o populations of plasma cells, i.e. lymphoplasmocytoid plasma cells located in the germinal center of lymphoid organs and reticular plasma cells at th e paracortex or medullary cords of secondary lymphoid tissues, were disting uished. Wue-1 is expressed when B-cell markers become lost and secretory ac tivity with plasma cell morphology appears. Cell surface markers were ident ified on normal plasma cells and compared with their malignant counterpart in vivo. Terminal plasma-cellular differentiation of malignant low- and hig h-grade B-cell lymphoma and anaplastic plasmacytoma, otherwise difficult to identify with conventional B-cell markers on tissue sections or fluorescen ce-activated cell sorter analyses, were detectable by Wue-1. In cell cultur e, Wue-1 enhanced the proliferation of myeloma cell lines but not normal pl asma cells in a dose-dependent manner. Since Wue-1-induced proliferation wa s increased by interleukin (IL)-6, Wue-1 recognizes a so far unidentified a ntigen with functional properties. Therefore, Wue-1 represents a useful new tool for therapy and for the in vivo and in vitro studying of B-cell lymph omas and the mechanisms of B-cell differentiation.