TCR-GAMMA-DELTA CELLS - MYSTERIOUS CELLS OF THE IMMUNE-SYSTEM

gamma delta cells participate in pathogenic infections and autoimmune conditions, yet, almost a decade after their discovery, little is know n regarding their TCR repertoire or effector functions. Unlike MHC-res tricted antigen recognition employed by TCR alpha beta cells, TCR gamm a delta cells can recognize whole unprocessed antigens in an MHC-indep endent manner. The nature of positive and negative selection used to s hape the repertoire of TCR gamma delta cells is unclear, especially in the nonlymphoid tissues where these cells predominate. While TCR gamm a delta cells express an activated phenotype and are present in pathol ogical conditions, their roles in immunological protection is unknown. This review will focus on our efforts to study these issues of TCR ga mma delta biology.