Analysis of early antigenic changes on heterokaryons between L-cells and a teratocarcinoma-derived cell line, TerC.

A method is presented for the detection of antigenic changes in heterokaryons during the first 24 h after fusion, as detected by antibody- and complement-mediated inhibition of 125IDU uptake. The method employs a variation of the HAT selection protocol, and a mathematical model which allows the reactions of a minority population of heterokaryons to be distinguished from those of the parental cells. This procedure is applied to fusions of clones of the teratocarcinoma-derived cell line TerC, which demonstrate very low levels of H-2b expression, with an L-cell derivative rich in H-2k antigens. Heterokaryons demonstrate an initial tendency for levels of H-2b and H-2k expression to converge, beginning within a few hours of fusion; however, H-2b expression never attains the levels of H-2k, even in long-term hybrids. These results are largely confirmed by quantitative absorptions, except that no diminution of H-2k expression is observed, suggesting that fusion with the TerC parents may transfer a resistance to complement damage to the L-cell parent.