title: IL-10 down-regulates costimulatory molecules on Mycobacterium tuberculosis-pulsed macrophages and impairs the lytic activity of CD4 and CD8 CTL in tuberculosis patients.
abstract: Activation of T cells requires both TCR-specific ligation and costimulation through accessory molecules during T cell priming. IFNgamma is a key cytokine responsible for macrophage activation during Mycobacterium tuberculosis (Mtb) infection while IL-10 is associated with suppression of cell mediated immunity in intracellular infection. In this paper we evaluated the role of IFNgamma and IL-10 on the function of cytotoxic T cells (CTL) and on the modulation of costimulatory molecules in healthy controls and patients with active tuberculosis (TB). gamma-irradiated-Mtb (i-Mtb) induced IL-10 production from CD14(+) cells from TB patients. Moreover, CD3(+) T cells of patients with advanced disease also produced IL-10 after i-Mtb stimulation. In healthy donors, IL-10 decreased the lytic activity of CD4(+) and CD8(+) T cells whereas it increased gammadelta-mediated cytotoxicity. Furthermore, we found that the presence of IL-10 induced a loss of the alternative processing pathways of antigen presentation along with a down-regulation of the expression of costimulatory molecule expression on monocytes and macrophages from healthy individuals. Conversely, neutralization of endogenous IL-10 or addition of IFNgamma to either effector or target cells from TB patients induced a strong lytic activity mediated by CD8(+) CTL together with an up-regulation of CD54 and CD86 expression on target cells. Moreover, we observed that macrophages from TB patients could use alternative pathways for i-Mtb presentation. Taken together, our results demonstrate that the presence of IL-10 during Mtb infection might contribute to mycobacteria persistence inside host macrophages through a mechanism that involved inhibition of MHC-restricted cytotoxicity against infected macrophages.
authors.affiliation: Departamento de Inmunología, Instituto de Investigaciones Hematológicas, Academia Nacional de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors.forename: S
authors.initials: S
authors.lastname: de la Barrera
authors.forename: M
authors.initials: M
authors.lastname: Aleman
authors.forename: R
authors.initials: R
authors.lastname: Musella
authors.forename: P
authors.initials: P
authors.lastname: Schierloh
authors.forename: V
authors.initials: V
authors.lastname: Pasquinelli
authors.forename: V
authors.initials: V
authors.lastname: Garcia
authors.forename: E
authors.initials: E
authors.lastname: Abbate
authors.forename: M del C
authors.initials: Mdel C
authors.lastname: Sasiain
mesh_terms: D000328:Adult; D000368:Aged; D017951:Antigen Presentation / Q000276:immunology; D015703:Antigens, CD / Q000276:immunology; D051940:B7-2 Antigen; D017252:CD3 Complex / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D019013:CD40 Antigens / Q000276:immunology; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology; D007371:Interferon-gamma / Q000276:immunology; D016753:Interleukin-10; D007963:Leukocytes, Mononuclear / Q000276:immunology; D018950:Lipopolysaccharide Receptors / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D008264:Macrophages / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000276:immunology; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014397:Tuberculosis, Pulmonary / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D051940:B7-2 Antigen; D017252:CD3 Complex; D019013:CD40 Antigens; C497964:CD86 protein, human; D018950:Lipopolysaccharide Receptors; D008562:Membrane Glycoproteins; D018799:Intercellular Adhesion Molecule-1; D016753:Interleukin-10; D007371:Interferon-gamma