Possible enzyme deficiency in bovine lymphosarcoma cells grown in vitro.

A culture of bovine lymphosarcoma cells was unable to grow in HAT medium, suggesting that the cells were unable to use either exogenous hypoxanthine or exogenous thymidine. Further work showed that they were able to incorporate tritiated thymidine but not tritiated guanine. This indicated that failure to grow in HAT medium was due to the cells being deficient in the enzyme hypoxanthine guanine phosphoribosyl transferase which is responsible for incorporation of the bases hypoxanthine and guanine. This finding may have application in the therapy of bovine lymphosarcoma.