γδ T Cells Exhibit Multifunctional and Protective Memory in Intestinal Tissues

• Mucosal memory γδ T cells are generated after oral infection
• Lm-elicited γδ T cells produce high amounts of both IL-17A and IFN-γ
• Mucosal memory γδ T cells generate a bacteria-specific secondary response
• Memory γδ T cells contribute to protection after re-exposure

SummaryThe study of T cell memory and the target of vaccine design have focused on memory subsumed by T cells bearing the αβ T cell receptor. Alternatively, γδ T cells are thought to provide rapid immunity, particularly at mucosal borders. Here, we have shown that a distinct subset of mucosal γδ T cells mounts an immune response to oral Listeria monocytogenes (Lm) infection and leads to the development of multifunctional memory T cells capable of simultaneously producing interferon-γ and interleukin-17A in the murine intestinal mucosa. Challenge infection with oral Lm, but not oral Salmonella or intravenous Lm, induced rapid expansion of memory γδ T cells, suggesting contextual specificity to the priming pathogen. Importantly, memory γδ T cells were able to provide enhanced protection against infection. These findings illustrate that γδ T cells play a role with hallmarks of adaptive immunity in the intestinal mucosa.

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