IgG opsonization of HIV impedes provirus formation in and infection of dendritic cells and subsequent long-term transfer to T cells

J Immunol. 2007 Jun 15;178(12):7840-8. doi: 10.4049/jimmunol.178.12.7840.

Abstract

Already at initial phases of infection, HIV is coated with complement fragments. During the chronic phase, when HIV-specific IgGs appear, the virus circulates immune complexed with IgG and complement. Thus, we studied the interaction of dendritic cells (DCs) and DC-T cell cocultures with complement (C)-opsonized and C-IgG-opsonized HIV. HIV infection of monocyte-derived DCs and circulating BDCA-1-positive DCs was significantly reduced upon the presence of virus-specific but non-neutralizing IgGs. DCs exposed to C-Ig-HIV or IgG-opsonized HIV showed an impaired provirus formation and p24 production and a decreased transmission rate to autologous nonstimulated T cells upon migration along a chemokine gradient. This reduced infectivity was also observed in long-term experiments, when T cells were added delayed to DCs exposed to IgG-coated HIV without migration. Similar kinetics were seen when sera from HIV-1-infected individuals before and after seroconversion were used in infection assays. Both C- and C-IgG-opsonized HIV were captured and targeted to a tetraspanin-rich endosome in immature DCs, but differed with respect to MHC class II colocalization. The reduced infection by IgG-opsonized HIV is possibly due to interactions of virus-bound IgG with FcgammaRIIb expressed on DCs. Therefore, the intracellular fate and transmission of immune-complexed HIV seems to differ depending on time and opsonization pattern.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Viral / immunology*
  • Antigens, CD / genetics
  • Antigens, CD / immunology
  • Coculture Techniques
  • Complement System Proteins / immunology
  • Dendritic Cells / virology*
  • HIV / immunology*
  • HIV Infections / immunology*
  • Humans
  • Immunoglobulin Fab Fragments / immunology
  • Immunoglobulin G / immunology*
  • Proviruses / immunology*
  • Receptors, IgG / genetics
  • Receptors, IgG / immunology
  • T-Lymphocytes / virology*

Substances

  • Antibodies, Viral
  • Antigens, CD
  • Fc gamma receptor IIB
  • Immunoglobulin Fab Fragments
  • Immunoglobulin G
  • Receptors, IgG
  • Complement System Proteins