Short running title: Phenotypic and functional characteristics of IL-15-differentiated DCs
ABSTRACT
IL-15 is an important cytokine involved in developmental process and functions of lymphoid cells such as NK cells and T cells. Although interests of IL-15-differentiated cells are increasing, there is still a debate for the role of IL-15 in dendritic cells, in particular during differentiation and priming. Here, we investigated phenotypic characters of IL-15 primed DCs and how they affect innate immunity during infection. When we compared the cytokine levels of cDCs (GC-cells) and IL-15 primed DCs (GC+IL-15-cells), only level of IFN-γ showed significant difference among detected cytokines, which was accompanied with decreased levels of CD11c and MHCII. Even though CD11cint population was pivotal factor of expressing IFN-γ, phenotypic markers did not reflect the characters of IKDCs, known for association with both IL-15 and IFN-γ, and pDCs. When B220, specifically increased in GC+IL-15-cells, was enriched, CD11cintThy1.2+Sca-1+ population produced IFN-γ. Interestingly, Thy1.2 and Sca-1 have never been reported as markers for GC+IL-15-cells. We applied GC+IL-15-cells which possessed targeted markers to M. tuberculosis infected macrophages to test the effect to innate immunity. The group cocultured with GC+IL-15-cells which have targeted markers showed suppression of bacterial growth. Overall, GC+IL-15-cells which are capable of producing IFN-γ have distinguished characters from those of other DCs, and could further improve for applying therapeutic ways for bacterial infection.