[AT191] HybridoXL™ Medium is a medium specially developed for propagation of hybridomas and other fastidious cell lines. It is a modified mixture of Dulbecco's Modified Eagle Medium and NCTC 135. On supplementation with 10% fetal bovine serum and insulin, it supports rapid growth of many hybridoma cell lines. AT191 contains L-glutamine and HEPES buffer. It does not contain insulin and sodium bicarbonate. This medium is supplied in two parts. Part A contains chemically defined media powder and Part B contains recombinant human insulin powder.