Inflammation alone evokes the response of a TCR-Invariant mouse gamma delta T cell subset

Whether gamma delta T lymphocytes respond to microbial Ags or to inducible host Ags remains a matter of controversy. Using several different disease m odels and mouse strains, we and others ha ce seen that V gamma 6/V delta 1 gamma delta T cells preferentially increase among the gamma delta T cells i nfiltrating inflamed tissues. However, it was not clear whether bacteria ar e necessary to bring about this response. Therefore, we hal-e reexamined th is question using a disease model in which inflammation is induced by a pur ely autoimmune process involving no bacteria, bacterial products, or other foreign material: testicular cell-induced autoimmune orchitis, Using this m odel we found that gamma delta T cells were still plentiful among the infil trating T lymphocytes. being 9- to 10-fold more prevalent than in spleen, a nd that V gamma 6/V delta 1(+) cells again represented the predominant gamm a delta T cell type. This finding shows that the response of the V gamma 6/ V delta 1(+) subset does not, in fact, depend upon the presence of bacteria or bacterial products, The stimulus triggering the response of the V gamma 6/V delta 1 gamma delta T cells appears to be neither foreign nor organ-sp ecific in origin, but instead consists of a self-derived host Ag or signal induced during the inflammatory process.