Biochemical characterization of regulatory factors derived from T cell hybridomas and spleen cells. I. Separation of T cell growth factor and T cell replacing factor from granulocyte-macrophage colony-stimulating factor.

We describe the molecular characteristics of T cell growth factor (TCGF), T cell replacing factor (TRF), and granulocyte-macrophage colony-stimulating factor (GM-CSF) produced by a T cell hybridoma after stimulation with concanavalin A (Con A). All three activities could be separated from Con A itself by ammonium sulfate precipitation. The TRF and TCGF activities had a m.w. of 35,000 to 40,000 on gel filtration in phosphate-buffered saline (PBS). Their m.w. were about 30,000 under dissociating conditions in guanidine hydrochloride and about 35,000 to 40,000 under disulfide reducing conditions, suggesting the molecule(s) lacked noncovalent or disulfide-linked subunit structure. GM-CSF had a m.w. of 25,000 to 30,000 by gel filtration in PBS and about 23,000 in guanidine hydrochloride. TRF and TCGF on the one hand and GM-CSF on the other could be distinguished by the criteria of m.w., relative heat sensitivity, and hydrophobic chromatography. TCGF could not be separated from TRF by any of these methods. In terms of all the above properties, factor derived from the T cell hybridoma and spleen cells appeared identical.