Expansion of a subset of CD14(high)CD16(neg)CCR2(low/neg) monocytes functionally similar to myeloid-derived suppressor cells during SIV and HIV infection

Monocytes 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.

National Institutes of Health

National Institutes of Health [MH070306, NS055648, MH085554]

Ministry of Health [914/BRA/3014-UNESCO/Kallas]

Ministry of Health

Sao Paulo City Health Department [2004-0.168.922-7/Kallas]

Sao Paulo City Health Department

Fundacao de Amparo a Pesquisa do Estado de Sao Paulo

Fundacao de Amparo a Pesquisa do Estado de Sao Paulo [04/15856-9/Kallas]

Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)

Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)

Brazilian Ministry of Education

Brazilian Ministry of Education

Brazilian Program for STD and AIDS

Brazilian Program for STD and AIDS