The role of dendritic cells in mycobacterium-induced granulomas

The presence of dendritic cells (DCs) in mycobacterium-containing granulomas, as well as in other granuloma-inducing diseases, is beginning to be appreciated. This review will summarize what is known about DCs with regards to the granuloma and discuss the potential roles DCs may be playing during mycobacterial infection. Potential functions may include mycobacterial dissemination from lesions or sampling of granuloma-containing mycobacterial antigens and migration to the draining lymph nodes to maintain continuous T cell priming. Additionally, the review will discuss the potential outcomes of DC–T cell cross-talk within the granuloma and whether it results in boosting the effector functions of newly arrived T cells or anergizing systemic T cells locally. Understanding the DCs complex and changing role during this critical stage may help explain how latency is achieved and maintained. Such knowledge might also lead to improved vaccination strategies.