Abstract
Interleukin-17A (IL-17A)-producing γδ T cells are known to be activated following Mycobacterium bovis bacillus Calmette-Guérin (BCG) infection. Here, we show that CD30, a member of the tumor necrosis factor (TNF) receptor superfamily, is important for activation of IL-17A-producing γδ T cells after BCG infection. Vγ1(-) Vγ4(-) γδ T cells preferentially expressing Vγ6/Vδ1 genes were identified as the major source of IL-17A in the peritoneal cavity during the early stage of BCG infection. The number of IL-17A-producing Vγ1(-) Vγ4(-) γδ T cells bearing Vγ6 increased in peritoneal exudate cells (PEC) of wild-type (WT) mice but not in those of CD30 knockout (KO) mice in response to BCG infection. Consistently, CD30 ligand (CD30L) or CD30 expression, predominantly by Vγ1(-) Vγ4(-) γδ T cells, was rapidly upregulated after BCG infection. Inhibition of CD30L/CD30 signaling by in vivo administration of a soluble CD30 and immunoglobulin fusion protein (CD30-Ig) severely impaired activation of IL-17A-producing Vγ1(-) Vγ4(-) γδ T cells in WT mice, while stimulating CD30L/CD30 signaling by in vivo administration of agonistic anti-CD30 monoclonal antibody (MAb) restored IL-17A production by Vγ1(-) Vγ4(-) γδ T cells in CD30L KO mice after BCG infection. These results suggest that CD30 signaling plays an important role in the activation of IL-17A-producing Vγ1(-) Vγ4(-) γδ T cells bearing Vγ6 at an early stage of BCG infection.