γδ T Cells Exhibit Multifunctional and Protective Memory in Intestinal Tissues

The study of Tcell memory and the target of vaccine design have focused on memory subsumed by Tcells bearing the αβ Tcell receptor. Alternatively, γδ Tcells are thought to provide rapid immunity, particularly at mucosal borders. Here, we have shown that a distinct subset of mucosal γδ Tcells mounts an immune response to oral Listeria monocytogenes (Lm) infection and leads to the development of multifunctional memory Tcells 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 Tcells, suggesting contextual specificity to the priming pathogen. Importantly, memory γδ Tcells were able to provide enhanced protection against infection. These findings illustrate that γδ Tcells play a role with hallmarks of adaptive immunity in the intestinal mucosa.