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Monocyte‐mediated T cell suppression by HIV‐2 envelope proteins
Author(s) -
Cavaleiro Rita,
Brunn Gregory J.,
Albuquerque Adriana S.,
Victorino Rui M. M.,
Platt Jeffrey L.,
Sousa Ana E.
Publication year - 2007
Publication title -
european journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 201
eISSN - 1521-4141
pISSN - 0014-2980
DOI - 10.1002/eji.200737511
Subject(s) - biology , t cell , monocyte , immunology , il 2 receptor , microbiology and biotechnology , immunosuppression , immune system
Abstract HIV‐2 is associated with an attenuated form of HIV disease. We investigate here the immunosuppressive effects of the HIV‐2 envelope protein, gp105. We found that gp105 suppresses activation of T cells through a monocyte‐mediated mechanism. Suppression of T cell activation by gp105 depends on contact between monocytes and T cells, but not on CD4 + CD25 + T cells. The TLR4 pathway is likely involved, since gp105 activates TLR4 signaling and induces TNF‐α production by monocytes. Immunosuppression is viewed as the main pathophysiologic consequence of infection by HIV. However, the main immunologic defect caused by HIV, depletion of T cells, requires T cell activation. Our findings are consistent with a new concept that HIV‐2 envelope proteins act on monocytes to suppress T cell activation and that this property may contribute to the benign course of HIV‐2. We hypothesize that the HIV‐2 envelope immunosuppressive properties limit bursts of T cell activation, thus reducing viremia and contributing to the slow rate of disease progression that characterizes HIV‐2 disease.