Subset-specific, uniform activation among Vγ6/Vδ1+ γδ T cells elicited by inflammation

The Vgamma6/Vdelta1(+) cells, the second murine gammadelta T cell subset to arise in the thymus, express a nearly invariant T cell receptor (TCR), colonize select tissues, and expand preferentially in other tissues during inflammation. These cells are thought to help in regulating the inflammatory response. Until now, Vgamma6/Vdelta1(+) cells have only been detectable indirectly, by expression of Vgamma6-encoding mRNA. Here, we report that 17D1, a monoclonal antibody, which detects the related epidermis-associated Vgamma5/Vdelta1(+) TCR, will also bind the Vgamma6/Vdelta1(+) cells if their TCR is first complexed to an anti-Cdelta antibody. Features of this special condition for recognition suggest the possibility that an alternate structure exists for the Vgamma6/Vdelta1 TCR, which is stabilized upon binding to the anti-Cdelta antibody. Using the 17D1 antibody as means to track this gammadelta T cell subset by flow cytometry, we discovered that the response of Vgamma6/Vdelta1(+) cells during inflammation often far exceeds that of other subsets and that the responding Vgamma6/Vdelta1(+) cells display a strikingly uniform activation/memory phenotype compared with other gammadelta T cell subsets.