Fast protein liquid chromatography of lymphocyte blastogenesis inhibitory factor produced by the human macrophage-like cell line U937.

The human macrophage-like cell line U937 constitutively produces a lymphocyte blastogenesis inhibitory factor (LBIF). Using fast protein liquid chromatography (FPLC)-chromatofocusing, FPLC-anion-exchange chromatography and high-performance liquid chromatography-gel permeation chromatography, LBIF has been purified to homogeneity. It is a single polypeptide chain and has a molecular weight of 57,000 daltons according to sodium dodecyl sulphate polyacrylamide gel electrophoresis under reducing conditions. LBIF shows pI 4.28-4.56 upon chromatofocusing on Mono P.