title: Preserved MHC class II antigen processing in monocytes from HIV-infected individuals.
abstract: BACKGROUND
  MHC-II restricted CD4+ T cells are dependent on antigen presenting cells (APC) for their activation. APC dysfunction in HIV-infected individuals could accelerate or exacerbate CD4+ T cell dysfunction and may contribute to increased levels of immunodeficiency seen in some patients regardless of their CD4+ T cell numbers. Here we test the hypothesis that APC from HIV-infected individuals have diminished antigen processing and presentation capacity.
  
  
  RESULTS
  Monocytes (MN) were purified by immuno-magnetic bead isolation techniques from HLA-DR1.01+ or DR15.01+ HIV-infected and uninfected individuals. MN were analyzed for surface MHC-II expression and for antigen processing and presentation capacity after overnight incubation with soluble antigen or peptide and HLA-DR matched T cell hybridomas. Surface expression of HLA-DR was 20% reduced (p<0.03) on MN from HIV-infected individuals. In spite of this, there was no significant difference in antigen processing and presentation by MN from 14 HIV-infected donors (8 HLA-DR1.01+ and 6 HLA-DR15.01+) compared to 24 HIV-uninfected HLA-matched subjects.
  
  
  CONCLUSIONS
  We demonstrated that MHC class II antigen processing and presentation is preserved in MN from HIV-infected individuals. This further supports the concept that this aspect of APC function does not further contribute to CD4+ T cell dysfunction in HIV disease.
authors.affiliation: Division of Infectious Diseases and HIV Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America.
authors.forename: Laila
authors.initials: L
authors.lastname: Woc-Colburn
authors.forename: Lavinia
authors.initials: L
authors.lastname: Smultea
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Ramachandra
authors.forename: David H
authors.initials: DH
authors.lastname: Canaday
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D000938:Antigen-Presenting Cells / Q000821:virology; D015496:CD4-Positive T-Lymphocytes / Q000821:virology; D015658:HIV Infections / Q000097:blood* / Q000821:virology*; D006684:HLA-DR Antigens / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D006825:Hybridomas / Q000276:immunology; D051379:Mice; D009000:Monocytes / Q000276:immunology* / Q000821:virology*
chemical_list: D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II