FLOW CYTOMETRIC ANALYSIS OF SIALYL-LEWIS A-ANTIGEN ON HUMAN CANCER-CELLS BY USING F(AB')(2-MU) FRAGMENTS PREPARED FROM A MOUSE IGM MONOCLONAL-ANTIBODY

F(ab')(2) fragments, herein designated as F(ab')(2 mu) fragments, were prepared from a mouse IgM monoclonal antibody specific to sialyl Lewi s A antigen. The fragments were applied to flow cytometry to analyze t he antigen on human cancer cells. The binding of the fragments to the antigen-positive cells was stronger than that of the original IgM. The non-specific binding of the IgM antibody to the antigen-negative cell s was much decreased by using the F(ab')(2 mu) fragments. These result s indicate that the F(ab')(2 mu) fragments are more suitable than the original IgM monoclonal antibody in flow cytometric analysis.