RPMI 1640 media were originally developed for suspension cultures or monolayer cultures of human leukemia cells. In addition, they intended to be used with a serum supplement. Recently, RPMI-1640 media have been shown to support several cell lines in the absence of serum. They have also been widely used in fusion protocols and in the growth of hybrid cells. HEPES buffer is included in the formulation at a final concentration of 25 mM to compensate for the loss of buffering capacity incurred by eliminating serum. RPMI 1640 with L-Glutamine and HEPES (RPMI 1640) is a sterile, liquid medium which contains essential and non-essential amino acids, vitamins, organic and inorganic compounds, hormones. It is well suited for supporting the growth of a broad range of mammalian cell lines. This product is for research use only. It is not approved for human or animal use, or for application in in vitro diagnostic procedures.