The kinetic study on cell surface antigens of a hybridoma between human B cells and a mouse B-cell line.

Human B cells obtained from tonsils were fused with a mutant clone of a murine B-cell line in the presence of polyethylene glycol and dimethyl sulfoxide. THT12.58, a subclone of the human-mouse B-cell hybridoma, was shown to express human B-cell surface antigens on the cell membrane, namely B1, B2, I2, human IgM and IgD derived from human B cells by analysis of flow microfluorometry (FMF), as well as murine B-cell markers; the amount of these human B-cell markers on THT12.58 did not change for more than 1 year after establishment. Interestingly, the expression of the human B-cell antigens significantly decreased after treatment of the cells with B-cell stimulatory factors (BSF) obtained from the supernatant of the culture of PHA-P activated T cells; this was followed by significant enlargement in cell size compared with the control. A marked decrease in the amount of each antigen on the hybrid was observed when treated with Staphylococcus aureus Cowan I strain (SAC) in addition to BSF. In contrast, the expression of these markers on the cells increased after exposure of the cells to recombinant human interferon-gamma (rINF-gamma). Additionally, the effect of BSF on the generation of IgM-secreting cells by human B cells markedly decreased after absorption of BSF with the hybrid cells. These results suggest that THT12.58 may possess a receptor for BSF on the cell surface, and be capable of differentiating into much more mature stage of B-cell lineage after exposure to BSF. Thus, this kind of a human-mouse B-cell hybridoma with human B-cell differentiation antigens can be a good model to investigate the kinetics of cell surface antigens and characterization of a receptor for BSF on human B cells.