PHENOTYPIC IDENTIFICATION OF SPECIFIC AND NONSPECIFIC SUPPRESSOR T-CELL POPULATIONS INVOLVED IN THE IN-VIVO RESPONSE TO ALLOANTIGEN

The monoclonal antibody 984.D4.6 (ma984) has been previously shown to recognize antigen-specific suppresser T-cells in an in vitro alloantig enic mixed-lymphocyte response system. In addition, an antiserum gener ated in rabbits to the N-terminal sequence of the nonspecific suppress or factor SIRS (soluble immune response suppressor) has been shown to block. the suppressive activity of nonspecific, concanavalin A-activat ed suppressor cells, In the present studies we have used these antibod ies to investigate the development of T-suppressor activity in mice im munized with alloantigen. These studies demonstrate the development of two populations of suppressor cells, one of which is antigen nonspeci fic and inhibitable with anti-SIRS and a second that is antigen-specif ic and sensitive to removal by lysis with ma984 plus complement. These populations of suppressor cells arise well after the peak of cytolyti c T-cell activity in response to alloantigen indicating asynchrony in the development of the immune response to alloantigen. (C) 1995 Academ ic Press, Inc.