Interaction of dendritic cells with mycobacteria: where the action starts.

Dendritic cells (DC) are the major antigen-presenting cells in the induction of cellular responses to intracellular pathogens, such as mycobacteria. Recent studies have shown that they also play a critical role in the regulation of immune responses. The interaction of DC with microbial antigens may be the controlling factor in the development of a Th1-orientated protective immunity. Analysis of the innate response of DC to mycobacteria and the involvement of the DC receptors in antigen recognition have highlighted the pivotal role of these cells in T-cell activation. Mycobacteria-infected DC have an enhanced capacity to release pro-inflammatory cytokines and chemokines and are potent inducers of interferon-gamma-producing cells in vivo. Therefore, DC manipulation for maximal antigen presentation and Th1 cytokine production may form the basis of a new generation of vaccines, with improved efficacy against mycobacterial infections.