Vaccinia virus decreases major histocompatibility complex (MHC) class II antigen presentation, T-cell priming, and peptide association with MHC class II

Immunology. 2009 Nov;128(3):381-92. doi: 10.1111/j.1365-2567.2009.03120.x.

Abstract

Vaccinia virus (VACV) is the current live virus vaccine used to protect humans against smallpox and monkeypox, but its use is contraindicated in several populations because of its virulence. It is therefore important to elucidate the immune evasion mechanisms of VACV. We found that VACV infection of antigen-presenting cells (APCs) significantly decreased major histocompatibility complex (MHC) II antigen presentation and decreased synthesis of 13 chemokines and cytokines, suggesting a potent viral mechanism for immune evasion. In these model systems, responding T cells were not directly affected by virus, indicating that VACV directly affects the APC. VACV significantly decreased nitric oxide production by peritoneal exudate cells and the RAW macrophage cell line in response to lipopolysaccharide (LPS) and interferon (IFN)-gamma, decreased class II MHC expression on APCs, and induced apoptosis in macrophages and dendritic cells. However, VACV decreased antigen presentation by 1153 B cells without apparent apoptosis induction, indicating that VACV differentially affects B lymphocytes and other APCs. We show that the key mechanism of VACV inhibition of antigen presentation may be its reduction of antigenic peptide loaded into the cleft of MHC class II molecules. These data indicate that VACV evades the host immune response by impairing critical functions of the APC.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigen Presentation
  • Antigens / immunology
  • Antigens / metabolism
  • Cell Line
  • Cytokines / biosynthesis
  • Cytokines / genetics
  • Dendritic Cells / immunology
  • Dendritic Cells / metabolism*
  • Dendritic Cells / pathology
  • Dendritic Cells / virology
  • Histocompatibility Antigens Class II / genetics
  • Histocompatibility Antigens Class II / immunology
  • Histocompatibility Antigens Class II / metabolism
  • Immune Evasion
  • Lymphocyte Activation
  • Macrophages, Peritoneal / immunology
  • Macrophages, Peritoneal / metabolism*
  • Macrophages, Peritoneal / pathology
  • Macrophages, Peritoneal / virology
  • Mice
  • Nitric Oxide / metabolism
  • Peptide Fragments / immunology
  • Peptide Fragments / metabolism
  • Protein Binding
  • Rats
  • Rats, Inbred Lew
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism*
  • T-Lymphocytes / pathology
  • Vaccinia / immunology*
  • Vaccinia / pathology
  • Vaccinia virus / immunology*
  • Vaccinia virus / pathogenicity
  • Virulence

Substances

  • Antigens
  • Cytokines
  • Histocompatibility Antigens Class II
  • Peptide Fragments
  • Nitric Oxide