Homology of partial primary sequences between alpha-enolase and a suppressive lymphokine from human T cells

A relationship is described between TS--a human suppressive lymphokine produced by hybridoma T cells--and alpha-enolase from the U937 monocyte human cell line. A strong homology (92%) was observed by comparing the internal amino acid sequences of 6 TS peptides, corresponding to 52 residues, with the complete sequence of alpha-enolase. The molecular masses of these two molecules were found to be of about 47 kDa and both were detected with the same monoclonal antibody to TS. In contrast, no immunosuppressive activity was detected with the purified enolase fraction, whereas TS did not show any enolase activity. A suppressive monokine secreted by U937 cells was found to be unrelated with TS. Theses results suggest that the TS immunosuppressive factor despite its absence of enzyme activity, belongs to the enolase family.