Time course study of H-2 and other antigen expression by hybrids of a myeloma cell line with inflammatory macrophages.

The hybrids (the CANS lines) between inflammatory macrophages from C57BL/6N (B6) mice (H-2b) and BALB/c mouse (H-2d)-derived myeloma cell line NS1 in the early period after cell fusion showed no macrophage functions. However, most of the hybrids expressed these functions after prolonged cultivation accompanied with chromosome loss. In contrast, the hybrids initially displaying myeloma functions (kappa light chain production) lost this function when they exhibited macrophage functions. We studied the expression of cell-surface antigens in these hybrids and found that hybrids in the early period after cell fusion codominantly expressed both parental cell H-2 antigens (H-2Kb, H-2Kd, and H-2Dd) but not the H-2Db antigen. On the other hand, aged hybrids strongly expressed the H-2d antigen but lacked the H-2Kb antigen. Alternatively, these aged hybrids with macrophage functions expressed antigen(s) as detected with antiaged CANS-196 cell sera and asialo GM1 antigen, both of which were thought to be found exclusively on macrophages. Thus, the expression of cell-surface antigens in these hybrids was greatly altered after cell fusion.