Brucella β 1,2 Cyclic Glucan Is an Activator of Human and Mouse Dendritic Cells

Bacterial cyclic glucans are glucose polymers that concentrate within the periplasm of alpha-proteobacteria. these molecules are necessary to maintain the homeostasis of the cell envelope by contributing to the osmolarity of gram negative bacteria. here,we demonstrate that brucella β 1,2 cyclic glucans are potent activators of human and mouse dendritic cells. dendritic cells activation by brucella β 1,2 cyclic glucans requires tlr4,myd88 and trif,but not cd14. the brucella cyclic glucans showed neither toxicity nor immunogenicity compared to lps and triggered antigen-specific cd8+ t cell responses in vivo. these cyclic glucans also enhanced antigen-specific cd4+ and cd8+ t cell responses including cross-presentation by different human dc subsets. brucella β 1,2 cyclic glucans increased the memory cd4+ t cell responses of blood mononuclear cells exposed to recombinant fusion proteins composed of anti-cd40 antibody and antigens from both hepatitis c virus and mycobacterium tuberculosis. thus cyclic glucans represent a new class of adjuvants,which might contribute to the development of effective antimicrobial therapies. © 2012 martirosyan et al.