Th17 cytokines and vaccine-induced immunity

Abstract

T helper type 17 (Th17) cells are a distinct lineage of T cells that produce the effector molecules IL-17, IL-17F, IL-21, and IL-22. Although the role of Th17 cells in primary immune responses against infections is well documented, there is growing evidence that the Th17 lineage maybe critical for vaccine-induced memory immune responses against infectious diseases. Here, we summarize recent progress in our understanding of the role of IL-17 in vaccine-induced immunity.

Figure 1. Model of vaccine-induced IL-17 in conferring protection against pathogens

Vaccination induces the generation of both Th1 and Th17 cells. Following challenge with pathogen, there is an expansion of memory Th17 cells and the production of IL-17. IL-17 can upregulate CXCR3 ligands resulting in augmented recruitment of Th1 effectors, production of IFNγ, leading to control of intracellular pathogens. Vaccine-induced IL-17 can augment chemokine induction by epithelial cells, resulting in recruitment of neutrophils, monocytes and macrophages, and enhance killing in phagocytic cells. IL-17 also augments induction of antimicrobial peptides important for control of extracellular pathogens.