Somatic cell genetics of human interferon production in human-rodent cell hybrids

Forty-two primary human-mouse cell hybrids, derived in two separate experiments, were treated with Newcastle disease virus (NDV): eight hybrids were found to produce human interferon and this was shown in every case to be predominantly of the fibroblast type. An extensive analysis was made in terms of karyotype and marker enzymes on all the eight hybrids producing interferon and also on five hybrids which did not produce interferon, five randomly selected hybrids and eleven subclones resistant to diphtheria toxin. The results suggest that, contrary to previous reports, a gene on chromosome 5 is not involved in production of human interferon. Its production was however correlated with the presence of chromosome 9 in the hybrids. Analyses of two sets of human-Chinese hamster hybrid subclones from two different crosses were also consistent with the assignment of a human interferon gene to chromosome 9.