Lymphocyte surface marker expression on hybridomas secreting human monoclonal antibodies

The expression of human leucocyte markers on the surface of hybridoma cell lines producing human monoclonal antibodies was studied using immunofluorescence analysis (FACS). We tested 36 different hybridoma cell lines from fusions of lymphocytes of different organs of fetal and adult organisms with the mouse myeloma line P3 X63 Ag8.653 or the mouse-human heteromyeloma line CB-F7 (IgM-, IgG-, and nonproducer) with a panel of 21 murine monoclonal antibodies against human differentiation and activation antigens. CD2, 3, 4, 5, 8, 10, 23, 25 antigen and major histocompatibility complex (MHC) class II determinants could not be detected on all hybridomas analyzed. The antigens CD22, 69, 71, and 72 were expressed on few of the hybridomas tested. The majority of the cell lines carried the surface markers CD19, 20, 40, 45 as well as the plasma cell markers CD38 and O/C11. The activation antigen 4F2 was expressed on all the cell lines tested. However, a direct connection between the expression of a lymphocyte marker and the capacity for Ig production (high and low producer; Ig isotype), the origin of the lymphocytes, and the fusion cell line used could not be detected.