IL-15 differentially affects the migratory capacity of young and aged memory CD8 T cells to mucosal sites.

Given that CD4 T cells are targets of depletion by HIV and required for the homing capacity of CD8 T cells, enhancing recruitment of both CD4 and CD8’s could potentially enhance protection against HIV infection. CD8 T cells at the site of infection are critical for clearance of HIV-infected cells. Memory CD8 T cells migrate into the periphery in the absence of “CD4 help”, homeostatically. However, migration to mucosal tissues such as the gut, require up-regulation of chemokine receptors, intergrins and other signals to gain entry. γC cytokines are key components of CD4 and CD8 T cell survival and maintenance. To date, the specific role of γC cytokines on migration of antigen-specific memory CD8 T cells to mucosal tissues is poorly understood. We show that IL-15 complex treatment drives migration of memory CD8 T cells to mucosa tissues such as the lung and lamina propria of the small intestine (SI LP). However, if the memory cells are aged then migration of CD8 T cells to the mucosal tissues is limited to the lung. These data reveal a novel role of for IL-15 for use as a potential vaccine adjuvant to enhance migration of young memory CD8 T cells to mucosal sites of infection and enhance protection against HIV infection.