Characterization of N-terminal amino acid sequence of monoclonal nonspecific suppressor factor.
Monoclonal nonspecific suppressor factor (MNSF), a product of a murine T cell hybridoma, suppresses the antibody response to lipopolysaccharide. In an attempt to clarify the N-terminal sequence, MNSF was prepared and purified by affinity chromatography with the use of an anti-MNSF monoclonal antibody (MO6), and reverse-phase high-pressure liquid chromatography. On the SDS-PAGE, the purified MNSF showed a single band with a molecular weight of 12,000. The N-terminal amino acid sequence of the protein was determined and showed no strong homology to any of the sequences of known biologically active proteins. However, the sequence revealed significant (60%) amino acid identity to transforming growth factor beta 2 (TGF beta 2).