IMMUNOLOGY : Another immune evasion strategy by HIV

Interaction of the human immunodeficiency virus (HIV) with dendritic cells—a specialized type of immune cell—circumvents immune activation and greatly enhances infection of T lymphocytes, reports a study to be published in the June issue of Nature Immunology.
Dendritic cells are required to initiate immune responses, and as targets of HIV infection, these cells are important contributors to HIV pathogenesis. Alison Simmons and colleagues evaluated the effect of HIV interaction with DC-SIGN, a protein receptor found largely on the surface of dendritic cells. HIV binding to DC-SIGN elicited a signalling pathway that prevented dendritic cells from actively stimulating subsequent immune responses. In addition, the authors show that HIV–DC-SIGN interaction can lead to transfer of virus to nearby T lymphocytes that then become infected leading to a burst of HIV production.
These results reveal how HIV can both evade dendritic cell immune activity and amplify its own replication. With nearly 40 million people world-wide currently living with HIV-AIDS, understanding the myriad ways that HIV can modulate immune responses is of paramount importance.
Author contact:
Alison Simmons (Weatherall Institute of Molecular Medicine, Oxford, UK)
Tel: +44 1865 222 616; E-mail: asimmons@hammer.imm.ox.ac.uk

Additional contact for comment:
Anthony Cunningham (Westmead Millennium Institute, Australia)
Tel: +61 2 9845 9005; E-mail: tony_cunningham@wmi.usyd.edu.au