Published in:
01-03-2013 | Immunology in Colorado
A canonical Vγ4Vδ4+ γδ T cell population with distinct stimulation requirements which promotes the Th17 response
Authors:
Christina L. Roark, Yafei Huang, Niyun Jin, M. Kemal Aydintug, Tamara Casper, Deming Sun, Willi K. Born, Rebecca L. O’Brien
Published in:
Immunologic Research
|
Issue 1-3/2013
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Abstract
We previously reported a subset of γδ T cells in mice which preferentially responds following intradermal immunization with collagen in complete Freund’s adjuvant (CFA). These cells express a nearly invariant “canonical” Vγ4Vδ4+ TCR. They are potent producers of IL-17A and promote the development of collagen-induced arthritis. In this study, we report that CFA emulsified with PBS alone (without collagen) is sufficient to induce a strong response of Vγ4Vδ4+ cells in the draining lymph nodes of DBA/1 and C57BL/6 mice and that the TCRs of the elicited Vγ4Vδ4+ cells in both strains heavily favor the canonical sequence. However, although both CFA and incomplete Freund’s adjuvant (which lacks the killed mycobacteria present in CFA) induced Vγ4Vδ4+ γδ T cell to expand, only CFA stimulated them to express IL-17A. The route of immunization was also critical, since intraperitoneal CFA induced only a weak response by these cells, whereas intradermal or subcutaneous CFA strongly stimulated them, suggesting that the canonical CFA-elicited Vγ4Vδ4+ cells are recruited from Vγ4+ γδ T cells normally found in the dermis. Their IL-17A response requires the toll-like receptor adapter protein MyD88, and their activation is enhanced by IFNγ, although αβ T cells need not be present. The CFA-elicited Vγ4Vδ4+ γδ T cells show a cytokine profile different from that of other previously described IL-17-producing γδ T cells. Finally, the Vγ4Vδ4+ subset appears to promote the Th17 αβ T cell response, suggesting its importance in mounting an effective immune response against certain pathogens.