The article discusses research being done on γδ T cells and its ability to provide long-lasting memory responses in the intestinal mucosa. It references a study by B. S. Sheridan and colleagues which appeared in a 2013 issue of "Immunity." A modified strain of Listeria monocytogenes was used in this study. Results of the study showed that only the CD27-CD44 γδ T cell subset responsed to Listeria monocytogenes.