Studies on migration inhibitory factor (MIF): Recovery of MIF activity after purification by gel filtration and disc electrophoresis

Abstract

Migration inhibitory factor (MIF) obtained from sensitized guinea pig lymph node lymphocytes stimulated by specific antigen ( o-chlorobenzoylbovine gamma globulin) in the absence of serum was characterized by Sephadex G-100 gel filtration, sucrose gradient centrifugation, and disc electrophoresis. Peak MIF activity was found after Sephadex gel filtration or sucrose gradient centrifugation in fractions containing molecules slightly smaller than albumin, indicating a molecular weight range of 35–55,000. No MIF activity was found in fractions containing molecules the size of immunoglobulins or in the fractions containing small molecular substances, such as lysozyme. A method was developed for preparing acrylamide gels from which material could be eluted which is nontoxic to cells in culture. When MIF-rich Sephadex fractions were further fractionated by disc electrophoresis at pH 9.1, peak MIF activity was consistently eluted from the fraction containing molecules migrating anodally to albumin. The three procedures employed demonstrated that MIF activity could be separated from albumin on the basis of size and charge.