• antigen presentation;
  • costimulation;
  • cross-presentation;
  • C-type lectin receptors;
  • dendritic cells;
  • MHC class I;
  • MHC class II;
  • pattern recognition receptors;
  • toll-like receptors;
  • trafficking

Dendritic cells are innate sentinels of the immune system and potent activators of naÏve T cells. Mechanisms must exist to enable these cells to achieve maximal activation of T cells specific for microbial antigens, while avoiding activation of T cells specific for self-antigens. Here we discuss how a combination of signals from pattern recognition receptors and T cells co-ordinates subcellular trafficking of antigen with both major histocompatibility complex class I and class II molecules and T-cell costimulatory molecules, resulting in the preferential presentation of microbial peptides within a stimulatory context.

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