Characterization of a T cell-derived lymphokine that acts synergistically with IL 3 on the growth of murine mast cells and is identical with IL4

Abstract A mast cell-like cell line (SN-1) was established with the aid of growth factor(s) present in the supernatant of a Con A-stimulated L3T4 + T cell line. In analogy to other mast cell lines, IL 3 was identified as a growth factor for SN-1 cells. In addition, a second lymphokine produced by the T cells synergistically enhanced the IL 3-induced growth. This factor, originally termed mast cell growth enhancing factor (MaGEF), could be separated from IL 2, IL 3, a CSF-like activity and was purified to homogeneity. The N-terminal amino acid sequence (8 residues) and the functional properties of this lymphokine proved to be identical with those reported for BSF-1 (IL 4). Unless applied at …