Abstract
The enormous number of commensal bacteria in the lower intestine of vertebrates share abundant molecular patterns used for innate immune recognition of pathogenic bacteria. We show that, even though commensals are rapidly killed by macrophages, intestinal dendritic cells (DCs) can retain small numbers of live commensals for several days. This allows DCs to selectively induce IgA, which helps protect against mucosal penetration by commensals. The commensal-loaded DCs are restricted to the mucosal immune compartment by the mesenteric lymph nodes, which ensures that immune responses to commensal bacteria are induced locally, without potentially damaging systemic immune responses.
Publication types
- Research Support, Non-U.S. Gov't
MeSH terms
- Animals
- Antigen Presentation
- B-Lymphocytes / immunology
- Bacteria / growth & development
- Bacteria / immunology*
- Bacteria / isolation & purification
- Dendritic Cells / immunology*
- Dendritic Cells / microbiology*
- Enterobacter cloacae / growth & development
- Enterobacter cloacae / immunology
- Enterobacter cloacae / isolation & purification
- Germ-Free Life
- Immunity, Innate
- Immunity, Mucosal*
- Immunoglobulin A / biosynthesis*
- Immunoglobulin A / blood
- Immunoglobulin A / immunology
- Intestinal Mucosa / immunology*
- Intestinal Mucosa / microbiology
- Intestines / microbiology*
- Leukocytes / immunology
- Leukocytes / microbiology
- Lymph Nodes / cytology
- Lymph Nodes / immunology
- Lymph Nodes / microbiology
- Macrophages / immunology
- Macrophages / microbiology
- Mesentery
- Mice
- Mice, Inbred C57BL
- Peyer's Patches / cytology
- Peyer's Patches / immunology
- Phagocytosis
- Salmonella typhimurium / growth & development
- Salmonella typhimurium / immunology
- Salmonella typhimurium / isolation & purification
- Specific Pathogen-Free Organisms
- Spleen / cytology
- Spleen / microbiology