Analysis Of Hematopoietic-Cells In Rat Bone-Marrow And Fetal Liver With Monoclonal-Antibody

The expression of cell surface antigens recognized by UB-12 monoclonal antibody against rat hemopoietic cells was examined in fetal liver, and adult bone marrow using immunohistochemistry, radioimmunoassay, and flow cytofluorometry. Comparisons were made with the expression of the antigens recognized by OX-7 (anti-Thy-1) or W3/13 (anti-leukocyte sialoglycoprotein) antibodies. UB-12 positive cells appeared at earlier stages of gestation and in higher cell frequency than OX-7 or W3/13 positive cells in fetal liver. The antigen detected with UB-12 antibody was positive in fetal liver at day 12 and increased at day 15, reaching about 90% of the positive cells. In bone marrows, UB-12 positive cells started to appear around birth and were about 30-40% of total nucleated cells during adult periods. Thus, the antigen recognized by UB-12 was found only during early stages of blood cells. UB-12 monoclonal antibody recognized a B-cell lymphoma, Y-3, but did not react with a rat T lymphoma cell line. This monoclonal antibody may be important for distinguishing normal and neoplastic B cells and their precursors.