title: Effects of Streptococcus mutans on dendritic cell activation and function.
abstract: Despite existing preventive and therapeutic measures, caries remains a ubiquitous infectious disease. Vaccine studies suggest that an adaptive immune response, culminating in effective antibody production, may reduce an individual's susceptibility to caries. However, the efficacy of the immune response elicited by mutans streptococci in the oral cavity remains controversial. A greater understanding of the early stages of the adaptive immune response to cariogenic bacteria may potentially assist therapeutic targeting and design. We therefore sought to characterize dendritic cell (DC) activation and antigen presentation following Streptococcus mutans exposure. We found that S. mutans up-regulated DC expression of co-stimulatory molecules and MHCII in vitro and that DCs effectively processed and presented exogenously administered antigen. These DCs effectively initiated T-cell proliferation, but this was abrogated by live bacteria. The in vitro DC activation effects were not mirrored in vivo, where DCs in draining lymph nodes did not mature following oral exposure to S. mutans. Analysis of these data provides a model for studying antigen uptake from the oral cavity and evidence that, in vitro, S. mutans activates dendritic cells, a critical event for initiating adaptive immunity.
authors.affiliation: Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, Sir Graeme Davies Building, University of Glasgow, Glasgow, G12 8TA, United Kingdom.
authors.forename: J P
authors.initials: JP
authors.lastname: Butcher
authors.forename: J
authors.initials: J
authors.lastname: Malcolm
authors.forename: R A
authors.initials: RA
authors.lastname: Benson
authors.forename: D M
authors.initials: DM
authors.lastname: Deng
authors.forename: J M
authors.initials: JM
authors.lastname: Brewer
authors.forename: P
authors.initials: P
authors.lastname: Garside
authors.forename: S
authors.initials: S
authors.lastname: Culshaw
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D001854:Bone Marrow Cells / Q000276:immunology / Q000382:microbiology; D002478:Cells, Cultured; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000276:immunology* / Q000382:microbiology*; D003733:Dental Caries Susceptibility; D005260:Female; D005434:Flow Cytometry; D005802:Genes, MHC Class II / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D013295:Streptococcus mutans / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology