Purification and properties of a factor from leukaemic T cells which non-specifically enhances the antibody response.

A non-specific immunoenhancing factor from leukemia owl monkey peripheral T lymphocytes has been purified and partially characterized. Owl monkey enhancing factor, OMEF, is a glycoprotein with a molecular weight of 39,000 and an isoelectric point of pH 6.5. It acts at nanogram levels on day 2 of the in vitro immune response to enhance the number of plaque-forming cells produced to sheep red blood cells in a murine assay system but has no effect when added on day 0 to this system but has no effect when added on day 0 to this system. Antibodies to the purified factor have been produced and binding studies show that OMEF cross-reacts with other antisera raised to an enhancing factor produced by a mixture of human allogeneic lymphocytes but shows no cross-reactivity to a murine enhancing factor.