TCR repertoire of suppressor CD8+CD28- T cell populations

The cellular basis of graft rejection and the development of strategies for specific suppression of T cell responses against allogeneic and xenogeneic transplants represents an area of active investigation. Recently, a population of MHC-class I restricted CD8(+)CD28(-) T suppressor cells (Ts) which are able to inhibit specifically the proliferative response of allospecific, xenospecific and nominal-antigen specific CD4(+) T helper cells (Th) has been identified. We have studied the TCR V beta gene repertoire expressed by CD8(+)CD28(-) Ts isolated from allospecific, xenospecific, and nominal antigen-specific T cell lines (TCL). A limited V beta repertoire has been found in all TCLs studied. The most restricted TCR V beta usage was observed within the population of Ts from xenospecific TCLs. The TCR V beta usage within the Ts subset of TCL differs from the TCR repertoire expressed by the CD4(+) Th subset of the same TCL. This is consistent with the fact that Ts and Th cells recognize distinct MHC/antigen complexes. The finding that the TCR repertoire used by Ts is limited opens new avenues for studying the mechanisms of transplant rejection. Human Immunology 60, 291-304 (1999). (C) American Society for Histocompatibility and Immunogenetics, 1999 Published by Elsevier Science Inc.