Interaction of dendritic cells with mycobacteria: Where the action starts

Dendritic cells (DC) are the major antigen-presenting cells in the inductio n of cellular responses to intracellular pathogens, such as mycobacteria. R ecent studies have shown that they also play a critical role in the regulat ion 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 in volvement of the DC receptors in antigen recognition have highlighted the p ivotal role of these cells in T-cell activation. Mycobacteria-infected DC h ave an enhanced capacity to release pro-inflammatory cytokines and chemokin es and are potent inducers of interferon-gamma-producing cells in vivo. The refore, DC manipulation for maximal antigen presentation and Th1 cytokine p roduction may form the basis of a new generation of vaccines, with improved efficacy against mycobacterial infections.