T-cell hybridoma production of macrophage activation factor (MAF) I. Separation of MAF from interferon gamma.

A T cell hybridoma was developed that produced macrophage activation factor (MAF) but no gamma interferon (IFN gamma). Hybridoma MAF was produced after stimulation with either concanavalin A (Con A) or phytohemagglutinin (PHA). Dose-response experiments showed that 1.5 microgram/ml Con A provided maximum MAF production with equivalent levels of MAF produced at Con A concentrations up to 6 microgram/ml. Time-course studies showed that maximum MAF activity was observed 48 hours after mitogen stimulation, and titration of MAF-containing supernatants showed that maximal MAF activity was observed at 1:4 dilutions with significant activity present at dilutions as great as 1:64. No IFN gamma activity was detectable at any supernatant dilution.