Isolation and preliminary characterization of drug resistant mutants of human lymphoblastoid cells

Mutants of human lymphoblastoid cell lines have been isoalted, which are resistant to 6-thioguanine or to 2,6-diaminopurine. They have been partially characterized and shown to be almost totally deficient in HGPRT and APRT, respectively. Cell lines doubly mutant for HGPRT deficiency and resistance to ouabain have also been isolated. All mutants were indistinguishable from the respective parental lines by criteria other than those leading specifically to their drug resistant phenotypes. The use of these mutants in the production of hybrids between two lines of suspension-growing human lymphoblastoid cells is discussed.