RESPONSE OF A GAMMA-DELTA(-CELL RECEPTOR INVARIANT SUBSET DURING BACTERIAL-INFECTION() T)

Murine gamma delta T cells can be divided into subsets based on the TC R gamma-chains they express, Most of these subsets have variable TCR j unctions, but two, both associated with epithelia, express invariant T CRs, The absence of receptor variability in these cells implies unifor mity of their ligands, This was previously taken as evidence to sugges t that gamma delta T cells recognize host-derived, stress-induced liga nds, We now demonstrate, for the first time, the response of a gamma d elta TCR invariant subset during bacterial infection, a potential caus e of stress, After infection with Listeria monocytogenes, absolute num bers of all T cells in the liver, including alpha beta and gamma delta T cell subsets, increased markedly, However, responses of gamma delta T cell subsets varied. We noted a decrease in the relative frequency of V delta 6.3' cells, which are, for the most part, included in the V gamma 1(+) subset. In contrast, cells bearing the invariant V gamma 6 /V gamma 1 TCR increased substantially in proportion to other gamma de lta T cells, as determined by PCB analysis of liver T cell RNA and by comparing liver gamma delta T cell hybridomas made from normal mice to those from mice infected with Listeria. V gamma 6/V delta 1(+) cells have been previously reported as a TCR invariant intraepithelial subse t in the female reproductive tract and tongue, We show here that V gam ma 6/V delta 1(+) cells reactive in Listeria-infected liver are polycl onally derived, but still bear TCR chains with invariant junctional se quences, identical with those of the female reproductive tract, Althou gh the Ag that stimulates these cells is unknown, our results indicate that not only diverse, but also invariant, gamma delta T cell subsets can become involved in the host response to a bacterial infection.