A tissue culture medium containing hypoxanthine, aminopterin, and thymidine. Mutant cells deficient in or lacking the enzymes thymidine kinase (TK−) and hypoxanthine-guanine-phosphoribosyl transferase (HGPRT−) cannot grow in HAT medium because aminopterin blocks endogenous (de novo) synthesis of both purines and pyrimidines. Normal TK+ HGPRT+ cells can survive by utilizing the exogenous hypoxanthine and thymidine via the salvage pathway (q.v.) of nucleotide synthesis. HAT medium has been used to screen for hybridomas (q.v.) by mixing TK+ HGPRT− myeloma cells with antigen-stimulated TK− HGPRT+ spleen cells. The hybrid TK+ HGPRT+ clones that survive in HAT medium are then assayed for monoclonal antibodies specific to the immunizing antigen. See Chronology, 1964, Littlefield; 1967, Weiss and Green.
Subjects: Genetics and Genomics — Medicine and Health.