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

Abstract 

A new monoclonal antibody, Wue-1, which specifically recognizes normal and malignant plasma cells, is characterized. Biochemical studies showed that monoclonal antibodies (mAbs) recognize a protein of 94 kDa. Using triple-staining flow cytometry and double-labeling immunohistochemical techniques, two populations of plasma cells, i.e. lymphoplasmocytoid plasma cells located in the germinal center of lymphoid organs and reticular plasma cells at the paracortex or medullary cords of secondary lymphoid tissues, were distinguished. Wue-1 is expressed when B-cell markers become lost and secretory activity with plasma cell morphology appears. Cell surface markers were identified on normal plasma cells and compared with their malignant counterpart in vivo. Terminal plasma–cellular differentiation of malignant low- and high-grade B-cell lymphoma and anaplastic plasmacytoma, otherwise difficult to identify with conventional B-cell markers on tissue sections or fluorescence-activated cell sorter analyses, were detectable by Wue-1. In cell culture, Wue-1 enhanced the proliferation of myeloma cell lines but not normal plasma cells in a dose-dependent manner. Since Wue-1-induced proliferation was increased by interleukin (IL)-6, Wue-1 recognizes a so far unidentified antigen 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 lymphomas and the mechanisms of B-cell differentiation.