title: The effect of Chlamydophila pneumoniae Major Outer Membrane Protein (MOMP) on macrophage and T cell-mediated immune responses.
abstract: The Major Outer Membrane Protein (MOMP) belongs to the membrane complex of cysteine-rich proteins of Chlamydophila pneumoniae. Although MOMP can elicit strong immune responses it fails to confer long-term protection against infection in animal models. This effect has been attributed, at least in part, to an inadequate induction of protective Th1-mediated immune responses. In an effort to understand the cellular mechanisms associated to the immunomodulatory properties of MOMP we studied the effect of this protein on mouse macrophages and naïve T-lymphocytes. We found that incubation of mouse macrophages with recombinant MOMP (rMOMP) results in an increased secretion of MMP-9 and a down-regulation of MHC class II, CD86 and CD40. This was accompanied by an increase in IL-10 and IFNγ but not in IL-12 secretion. rMOMP induced a down-regulation of the expression of CD69 and CD154 markers by activated CD4(+) T cells, and enhanced the secretion of IL-2 and IL-10 by these cells. Conversely, rMOMP-treated macrophages up-regulated the expression of CD69 but not CD154, inhibited the synthesis of IL-10 and up-regulated the production of IFNγ by activated CD8(+) T cells. Immunization of mice with MOMP induced the synthesis only of MOMP-specific IgG1 but no differences in cytokine profile were observed compared to controls. Our results provide new evidence on the role of MOMP in modulating T cell-mediated immune responses.
authors.affiliation: University of Surrey, Faculty of Health and Medical Sciences, Guildford, UK.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Bermudez-Fajardo
authors.forename: Anne-Katrien
authors.initials: AK
authors.lastname: Stark
authors.forename: Rehab
authors.initials: R
authors.lastname: El-Kadri
authors.forename: Manuel L
authors.initials: ML
authors.lastname: Penichet
authors.forename: Katharina
authors.initials: K
authors.lastname: Hölzle
authors.forename: Max M
authors.initials: MM
authors.lastname: Wittenbrink
authors.forename: Ludwig
authors.initials: L
authors.lastname: Hölzle
authors.forename: Ernesto
authors.initials: E
authors.lastname: Oviedo-Orta
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D002478:Cells, Cultured; D016993:Chlamydophila pneumoniae / Q000276:immunology*; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000378:metabolism; D007111:Immunity, Cellular; D056724:Immunity, Humoral; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D011994:Recombinant Proteins; D058408:Th1-Th2 Balance
chemical_list: D015703:Antigens, CD; D001425:Bacterial Outer Membrane Proteins; D016207:Cytokines; D000949:Histocompatibility Antigens Class II; D011994:Recombinant Proteins; C101031:major outer membrane protein, Chlamydia pneumoniae; D020780:Matrix Metalloproteinase 9