RPMI-1640 was developed by Moore, et al. at Roswell Park Memorial Institute, hence the acronym RPMI. The formulation is based on the RPMI-1630 series of media utilizing a bicarbonate buffering system and alterations in the amounts of amino acids and vitamins. RPMI-1640 medium has been used for the culture of human normal and neoplastic leukocytes. RPMI-1640, when properly supplemented, has demonstrated wide applicability for supporting growth of many types of cultured cells, including fresh human lymphocytes in the 72 hour phytohemaglutinin (PHA) stimulation assay.