Vγ6+ γδ T cells play a critical role in protection against infection by Escherichia coli

γδ T cells producing interleukin 17A (IL-17A), which are mainly Vγ4 and Vγ6 subsets, are involved in protection against infection by extracellular bacteria. Using a new Vγ6-specific monoclonal antibody (mAb) (1C10-1F7) which we recently developed, we found that IL-17A+ Vγ6+ γδ T cells increased predominantly in the peritoneal cavity compared with IL-17A+ Vγ4+ γδ T cells during intraperitoneal Escherichia coli infection. The number of IL-17A+ Vγ6+ γδ T cells, which rapidly became CD69+ from CD69-, peaked at 12 h after infection. In vivo treatment with 1C10-1F7 mAb significantly inhibited the accumulation of neutrophils and hampered the resolution of E. coli infection. These results suggest that rapid activation of IL-17A+ Vγ6+ γδ T cells contributed to host defence against E. coli infection. Microarray analysis of gene expression in Vγ6+ γδT cells from the peritoneal cavity of mice before or 3 h after E. coli infection (1 replicate of cells from 20 mice per sample).