Human macromolecular insoluble cold globulin (MICG). I. T-cell origin of T-MICG and null cell origin of N-MICG.

Abstract

Although surface immunoglobulin characterizes B [bone marrow-derived] cells in man, there are few surface markers that distinguish T [thymus-derived] cells. A new protein synthesized in human T cells, termed T-MICG, was described. This protein is a macromolecule of 225,000 daltons, insoluble in the cold, and migrates as a .beta.-globulin on electrophoresis. Separation of human peripheral blood lymphocytes into T and B cell populations by rosette sedimentation and anti-human-Fab columns clearly demonstrated the T cell origin of the 225,000 dalton component. Null cells were shown to synthesize a protein of 185,000 daltons, termed N-MICG, with physical properties similar to T-MICG. T-MICG and N-MICG were antigenically dissimilar, employing antiserum to each of these proteins. Two novel cell surface markers, T-MICG and N-MICG, were demonstrated which characterize T cells and null cells, respectively.