Silencing T cells or T-cell silencing: concepts in virus-induced immunosuppression.
The ability to evade or suppress the host's immune response is a property of many viruses, indicating that this provides an advantage for the pathogen to spread efficiently or even to establish a persistent infection. The type and complexity of its genome and cell tropism but also its preferred type of host interaction are important parameters which define the strategy of a given virus to modulate the immune system in an optimal manner. Because they take a central position in any antiviral defence, the activation and function of T cells are the predominant target of many viral immunosuppressive regimens. In this review, two different strategies whereby this could be achieved are summarized. Retroviruses can infect professional antigen-presenting cells and impair their maturation and functional properties. This coincides with differentiation and expansion of silencing T cells referred to as regulatory T cells with suppressive activity, mainly to CD8+ effector T cells. The second concept, outlined for measles virus, is a direct, contact-mediated silencing of T cells which acquire a transient paralytic state.
Schneider-Schaulies
Sibylle
S
Institute for Virology, University of Würzburg, Versbacher Straße 7, D-97078 Würzburg, Germany.
Dittmer
Ulf
U
Institut für Virologie des Universitätsklinikums Essen, D-45122 Essen, Germany.
D002454:Cell Differentiation; D006801:Humans; D007165:Immunosuppression Therapy; D008213:Lymphocyte Activation / Q000276:immunology; D008459:Measles virus / Q000276:immunology* / Q000472:pathogenicity; D012190:Retroviridae / Q000276:immunology* / Q000472:pathogenicity; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000821:virology