Regulation of the Immune Response by Innate Lymphocyte and Dendritic Cell Cross Talk

Dendritic cell (DC) is the generic name of different professional antigen presenting cell sub-populations, which are responsible for the initiation of specific immune responses. Recently, DC have been involved in supporting innate immunity by interacting with various innate lymphocytes, such as natural killer (NK), NKT or γδ T (T cells expressing γδ T cell receptor). The functional links between innate lymphocytes and DC have been investigated widely and different studies demonstrated that the cross-talk between innate lymphocytes and DC was found to be multi-directional, involving not only cell-cell contacts but also soluble factors which lead to lymphocyte activation and DC maturation. The final outcome of these cellular interactions may have a dramatic impact on the quality and strength of the down-stream immune responses, mainly in the context of early responses to tumor cells and infectious agents. Interestingly, DC, NK and γδ T cells also share similar functions, such as antigen uptake and presentation, as well as cytotoxic and tumoricidal activity. In addition, NK and NKT cells have the ability to kill DC.
This chapter will focus upon the different aspects of the cross-talk between DC and innate lymphocytes and its key role in all the steps of the immune response. These cellular interactions may be particularly critical in situations where immune surveillance requires efficient early innate responses.