CD38 MOLECULE-A MULTILINEAGE GLYCOPROTEIN AND ITS UNIQUE EXPRESSION ON PLASMA CELLS

A hybridoma clone designated 6G5 has been selected by fusion of mouse myeloma cell line Ag. 8653 with spleen cells from mice immunized with human peripheral blood mononuclear cells (PBMC). The antibody produced by this clone was found to be strongly reactive with four human B-cell lines in the conventional immunological assays. Despite the fact that expression of most B cell-associated markers are lost upon differentiation of B-cells to plasma cells, the expression of the 6G5 reactive molecule remains unchanged. The lack of reactivities of this MAb for mature T-cells, and monocytic cell lines indicates that this MAb recognizes a B cell associated marker. Western blot analysis indicated that the 6G5 MAb detected a single band with molecular weight of 41 KDa from cell lysates of two human B-cell lines, DAUDI and NALM6. Comparison of data obtained for 6G5 MAb with those of the MAb known as OKTIO indicated that both MAbs may have reacted with the same molecule.