title: Chlamydia pneumoniae induces interleukin-10 production that down-regulates major histocompatibility complex class I expression.
abstract: Recently, it was demonstrated that CD8(+) T cells are important for the response against Chlamydia pneumoniae. By use of the human monocytic cell line U937 and human monocytes taken from peripheral blood, we investigated the effect of infection on various molecules critical for CD8(+) T cell function. A strong secretion of interleukin (IL)-10 by infected cells was observed, together with an inhibited expression of major histocompatibility complex (MHC) class I antigens, but without significant alteration of tumor growth factor-beta secretion or MHC class II expression. Recombinant IL-10 added to uninfected U937 cells decreased the expression of MHC class I, whereas blocking antibodies to IL-10 and its receptor abolished the C. pneumoniae-induced inhibition of MHC class I expression. Analysis of our data provides evidence that IL-10 secretion induced by C. pneumoniae infection of monocytic cells down-regulates the expression of MHC class I molecules and thereby might reduce the presentation of bacterial epitopes by MHC. This would decrease the ability of CD8(+) T cells to eliminate infected cells.
authors.affiliation: INSERM U466, Institut Louis Bugnard, CHU Rangueil, Toulouse, France.
authors.forename: S
authors.initials: S
authors.lastname: Caspar-Bauguil
authors.forename: B
authors.initials: B
authors.lastname: Puissant
authors.forename: D
authors.initials: D
authors.lastname: Nazzal
authors.forename: J C
authors.initials: JC
authors.lastname: Lefèvre
authors.forename: M
authors.initials: M
authors.lastname: Thomsen
authors.forename: R
authors.initials: R
authors.lastname: Salvayre
authors.forename: H
authors.initials: H
authors.lastname: Benoist
mesh_terms: D018821:CD18 Antigens / Q000096:biosynthesis; D016993:Chlamydophila pneumoniae / Q000502:physiology*; D015536:Down-Regulation; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis; D016753:Interleukin-10 / Q000096:biosynthesis*; D009000:Monocytes / Q000378:metabolism / Q000382:microbiology; D016212:Transforming Growth Factor beta / Q000096:biosynthesis; D020298:U937 Cells
chemical_list: D018821:CD18 Antigens; D015395:Histocompatibility Antigens Class I; D016212:Transforming Growth Factor beta; D018799:Intercellular Adhesion Molecule-1; D016753:Interleukin-10