Abstract: BACKGROUND ＆ AIM: Human somatic cells have species superiority over animal cells in genotoxicity assay. This study aimed to demonstrate the performance of specific gene mutation in two human lymphoblastoid cell lines with different p53 status for its further use in genotoxicity assay. MATERIALS AND METHODS: TK and HPRT mutation was induced by four chemical mutagens, including EMS (ethyl methanesulfonate), MMS (methyl methanesulfonate), GLY (glyoxal), OPD (o-phenylenediamine). Mutants were selected by microwell method. RESULTS： TK6-E6 was more tolerant to cytotoxic agents than TK6. All 4 agents induced positive mutation responses at two loci in two cell lines. The most sensitive mutation was at TK locus in TK6-E6. The RSC (rate of slow growth colonies) in TK6 was much lower than that in TK6-E6, and there was little variation in RSC to those mutagens. CONCLUSION: TK and HPRT mutation test in two cell lines could be used to assay genotoxicity. TK6-E6 was superior to TK6 in view of higher sensitivity and higher dosage treatment allowance.

Key words: human lymphoblastoid cell, mutation assay, methyl methanesulfonate, ethyl methanesulfonate, o-phenylenediamine, glyoxal