Effect of intercellular communication on the selection of intraspecific human hybrids in HAT and ouabain

Optimal conditions have been determined for selection of hybrids in HAT and ouabain (HOT) from the PEG-mediated fusion of OUAR/HGPRT-/G6PDA and OUAS/HGPRT+/G6PDB human diploid fibroblasts. In addition to the OUARHGPRT+G6PDAB tetraploid hybrids, several other types of HOT-resistant colonies were obtained from these fusions and identified by G6PD isozyme analysis and karyotyping as (1) hybrids contaminated with diploid parental cells, (2) symbiotic mixtures of the two types of parental cells, or (3) spontaneous OUAR mutants. The mechanism for parental cell growth in HOT is most likely the transfer of HAT resistance and/or ouabain resistance through gap junctions formed between resistant and sensitive cells.