Microspectrofluorometric analysis of surface antigens of murine melanoma and hamster peritoneal cell hybrids: Comparisons of species antigenicity, chromosome number, and tumorigenicity

Somatic cell hybrids from viral fusions of murine melanoma (PAZG) x Chinese hamster peritoneal cells (CH) were compared with respect to surface antigenicity, karyotype and tumorigenicity. One line, F57-(9), which arose from the hybridization of two CH cells and one PAZG cell, had slight (6%) CH chromosome loss but 80% PAZG chromosome loss after 10 months in culture. These cells expressed CH antigens strongly and PAZG antigens weakly. In comparison, another hybrid, F57-(7), formed from one CH and onze PAZG cell, lost 20% of its chromosomes after 10 months in vitro. These cells had a stronger expression of PAZG antigens and weaker expression of CH antigens than F57-(9). These findings indicate a direct relationship between chromosome number and antigenicity; tumorigenicity, however, does not appear to depend on the chromosome numbers of the parental cells.