Buffy coat preparations are suitable for use as a source of nucleated peripheral blood mononuclear leukocytes (PBMC). Buffy coat preparations are generally enriched for leukocytes (WBC) and contain trace amounts of red cells and other blood components. This product is prepared in a buffer composed of 20.5 mg/ml Dextrose, 4.2mg/ml Sodium Chloride, 8.0 mg/ml Citric Acid Tri-sodium, adjusted to pH 6.1.