IL-4-Producing V gamma 1(+)/V delta 6(+) gamma delta T Cells Sustain Germinal Center Reactions in Peyer's Patches of Mice

The mucosal immune system is the first line of defense against pathogens. Germinal centers (GCs) in the Peyer's patches (PPs) of the small intestine are constantly generated through stimulation of the microbiota. In this study, we investigated the role of gamma delta T cells in the GC reactions in PPs. Most gamma delta T cells in PPs localized in the GCs and expressed a TCR composed of V gamma 1 and V delta 6 chains. By using mice with partial and total gamma delta T cell deficiencies, we found that V gamma 1(+)/V delta 6(+) T cells can produce high amounts of IL-4, which drives the proliferation of GC B cells as well as the switch of GC B cells towards IgA. Therefore, we conclude that gamma delta T cells play a role in sustaining gut homeostasis and symbiosis via supporting the GC reactions in PPs.