Partial purification and characterization of a lymphotoxic factor from multiple sclerosis serum.

A factor found in the serums of some patients with multiple sclerosis has been shown to have a toxic effect on the normal, mature lymphocyte. This lymphotoxic factor is a protein that is stable to heating at 56 degrees C for 3 hours. It is a nondialyzable material, with recovery of lymphotoxic activity following 30 days of dialysis. Elution of lymphotoxic serum through Sepadex G-100 demonstrates toxic activity closely associated with albumin. Purification by elution through DEAE-cellulose yielded lymphotoxic activity. The lymphotoxic factor was inactivated by standard ammonium sulfate precipitation. Analysis of the effect on distinctive cell types within the total lymphocyte population demonstrated that the T lymphocyte was particularly sensitive.