title: Intestinal microbes affect phenotypes and functions of invariant natural killer T cells in mice.
abstract: OBJECTIVE
  Invariant natural killer T (iNKT) cells undergo canonical, Vα14-Jα18 rearrangement of the T-cell receptor (TCR) in mice; this form of the TCR recognizes glycolipids presented by CD1d. iNKT cells mediate many different immune reactions. Their constitutive activated and memory phenotype and rapid initiation of effector functions after stimulation indicate previous antigen-specific stimulation. However, little is known about this process. We investigated whether symbiotic microbes can determine the activated phenotype and function of iNKT cells.
  
  
  METHODS
  We analyzed the numbers, phenotypes, and functions of iNKT cells in germ-free mice, germ-free mice reconstituted with specified bacteria, and mice housed in specific pathogen-free environments.
  
  
  RESULTS
  Specific pathogen-free mice, obtained from different vendors, have different intestinal microbiota. iNKT cells isolated from these mice differed in TCR Vβ7 frequency and cytokine response to antigen, which depended on the environment. iNKT cells isolated from germ-free mice had a less mature phenotype and were hyporesponsive to activation with the antigen α-galactosylceramide. Intragastric exposure of germ-free mice to Sphingomonas bacteria, which carry iNKT cell antigens, fully established phenotypic maturity of iNKT cells. In contrast, reconstitution with Escherichia coli, which lack specific antigens for iNKT cells, did not affect the phenotype of iNKT cells. The effects of intestinal microbes on iNKT cell responsiveness did not require Toll-like receptor signals, which can activate iNKT cells independently of TCR stimulation.
  
  
  CONCLUSIONS
  Intestinal microbes can affect iNKT cell phenotypes and functions in mice.
authors.affiliation: La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Wingender
authors.forename: Dariusz
authors.initials: D
authors.lastname: Stepniak
authors.forename: Philippe
authors.initials: P
authors.lastname: Krebs
authors.forename: Lin
authors.initials: L
authors.lastname: Lin
authors.forename: Sara
authors.initials: S
authors.lastname: McBride
authors.forename: Bo
authors.initials: B
authors.lastname: Wei
authors.forename: Jonathan
authors.initials: J
authors.lastname: Braun
authors.forename: Sarkis K
authors.initials: SK
authors.lastname: Mazmanian
authors.forename: Mitchell
authors.initials: M
authors.lastname: Kronenberg
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D004926:Escherichia coli; D005434:Flow Cytometry; D005699:Galactosylceramides / Q000276:immunology*; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; D005856:Germ-Free Life; D007422:Intestines / Q000276:immunology / Q000382:microbiology*; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D055611:Natural Killer T-Cells / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D010641:Phenotype; D011948:Receptors, Antigen, T-Cell / Q000737:chemistry; D013047:Specific Pathogen-Free Organisms; D020578:Sphingomonas
chemical_list: D015415:Biomarkers; D016207:Cytokines; D005699:Galactosylceramides; D011948:Receptors, Antigen, T-Cell; C493154:alpha-galactosylceramide