Toll-like receptor 4-dependent activation of dendritic cells by β-defensin 2. (Reports)

β-Defensins are small antimicrobial peptides of the innate immune system produced in response to microbial infection of mucosai tissue and skin. We demonstrate that murine β-defensin 2 (mDF2β) acts directly on immature dendritic cells as an endogenous ligand for Toll-like receptor 4 (TLR-4), inducing up-regulation of costimulatory molecules and dendritic ceil maturation. These events, in turn, trigger robust, type 1 polarized adaptive immune responses in vivo, suggesting that mDF2β may play an important role in immunosurveillance against pathogens and, possibly, self antigens or tumor antigens.
Activation of innate immunity through pattern recognition receptors for ligands derived from evolutionarily distant pathogens provides essential signals for initiation of the adaptive immune response (1-3). Microbial infection activates the [...]