Sistema FMUSP-HC: Faculdade de Medicina da Universidade de São Paulo (FMUSP) e Hospital das Clínicas da FMUSPGAMA, LucioSHIRK, Erin N.RUSSELL, Julia N.CARVALHO, Karina I.LI, MingQUEEN, Suzanne E.KALIL, JorgeZINK, M. ChristineCLEMENTS, Janice E.KALLAS, Esper G.2013-07-302013-07-302012JOURNAL OF LEUKOCYTE BIOLOGY, v.91, n.5, p.803-816, 20120741-5400https://observatorio.fm.usp.br/handle/OPI/392Monocytes have been categorized in three main subpopulations based on CD14 and CD16 surface expression. Classical monocytes express the CD14(++)CD16(-) CCR2(+) phenotype and migrate to inflammatory sites by quickly responding to CCL2 signaling. Here, we identified and characterized the expansion of a novel monocyte subset during HIV and SIV infection, which were undistinguishable from classical monocytes, based on CD14 and CD16 expression, but expressed significantly lower surface CCR2. Transcriptome analysis of sorted cells demonstrated that the CCR2(low/neg) cells are a distinct subpopulation and express lower levels of inflammatory cytokines and activation markers than their CCR2(high) counterparts. They exhibited impaired phagocytosis and greatly diminished chemotaxis in response to CCL2 and CCL7. In addition, these monocytes are refractory to SIV infection and suppress CD8(+) T cell proliferation in vitro. These cells express higher levels of STAT3 and NOS2, suggesting a phenotype similar to monocytic myeloid-derived cells, which suppress expansion of CD8(+) T cells in vivo. They may reflect an antiproliferative response against the extreme immune activation observed during HIV and SIV infections. In addition, they may suppress antiviral responses and thus, have a role in AIDS pathogenesis. Antiretroviral therapy in infected macaque and human subjects caused this population to decline, suggesting that this atypical phenotype is linked to viral replication. J. Leukoc. Biol. 91: 803-816; 2012.engrestrictedAccessmacrophagesAIDSsimian immunodeficiency virusperipheral-blood monocyteschemokine receptor expressioncentral-nervous-systemdendritic cellscc-chemokinechemoattractant protein-1cerebrospinal-fluidinflammatory sitesphenotypic changesarticleCopyright FEDERATION AMER SOC EXP BIOL10.1189/jlb.1111579Cell BiologyHematologyImmunology