HIV envelope-mediated, CCR5/α4β7-dependent killing of CD4-negative γδ T cells which are lost during progression to AIDS

H Li, CD Pauza - Blood, The Journal of the American Society of …, 2011 - ashpublications.org
Blood, The Journal of the American Society of Hematology, 2011ashpublications.org
HIV infects and replicates in CD4+ T cells but effects on host immunity and disease also
involve depletion, hyper-activation, and modification of CD4-negative cell populations. In
particular, the depletion of CD4-negative γδ T cells is common to all HIV+ individuals. We
found that soluble or cell-associated envelope glycoproteins from CCR5-tropic strains of HIV
could bind, activates the p38-caspase pathway, and induce the death of γδ cells. Envelope
binding requires integrin α4β7 and chemokine receptor CCR5 which are at high levels and …
Abstract
HIV infects and replicates in CD4+ T cells but effects on host immunity and disease also involve depletion, hyper-activation, and modification of CD4-negative cell populations. In particular, the depletion of CD4-negative γδ T cells is common to all HIV+ individuals. We found that soluble or cell-associated envelope glycoproteins from CCR5-tropic strains of HIV could bind, activates the p38-caspase pathway, and induce the death of γδ cells. Envelope binding requires integrin α4β7 and chemokine receptor CCR5 which are at high levels and form a complex on the γδ T cell membrane. This receptor complex facilitated V3 loop binding to CCR5 in the absence of CD4-induced conformational changes. Cell death was increased by antigen stimulation after exposure to envelope glycoprotein. Direct signaling by envelope glycoprotein killed CD4-negative γδ T cells and reproduced a defect observed in all patients with HIV disease.
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