Cytokines in innate and adaptive immunity.

Cytokines and chemokines are hormone-like messengers which act to regulate the development and expression of the broad array of immune responses that are mounted against a variety of pathogens. As such, they are critical determinants of the types of cells which will regulate and participate in innate and adaptive immune responses, they may act both in highly localised environments but also in a systemic manner, and they may, themselves, directly mediate antimicrobial effector activities. In this article, we will outline current concepts of the activities of cytokines and chemokines in the immune response and discuss the various cell types, including dendritic cells and other antigen-presenting cells, T cells and B cells, which both produce and respond to these potent regulatory molecules.