title: Human regulatory T cells are targets for human immunodeficiency Virus (HIV) infection, and their susceptibility differs depending on the HIV type 1 strain.
abstract: Regulatory T cells (Treg) are a subpopulation of CD4(+) T cells characterized by the suppressive activity they exert on effector immune responses, including human immunodeficiency virus (HIV)-specific immune responses. Because Treg express CXCR4 and CCR5, they represent potential targets for HIV; however, Treg susceptibility to HIV infection is still unclear. We therefore performed an extensive study of Treg susceptibility to HIV, using lab strains and primary isolates with either CCR5 or CXCR4 tropism. Furthermore, we quantified HIV infection at early and late time points of the virus life cycle. We found that Treg were clearly susceptible to HIV infection. Circulating Treg were not preferentially infected with HIV compared to effector T cells (Teff) in vivo. Conversely, in vitro infection with either CCR5-using (R5) or CXCR4-using (X4) viruses occurred with different dynamics. For instance, HIV infection by R5 viruses (lab strains and primary isolates) resulted in lower levels of infection in Treg compared with Teff at both early and late time points. In contrast, X4 viruses induced higher levels of infection in Treg compared to Teff at early time points, but this difference disappeared at the late time points of the virus life cycle. Our results suggest that the relative susceptibility of Treg to HIV infection compared to Teff varies, depending on both viral and host factors. These variations may play an important role in HIV pathogenesis.
authors.affiliation: Division of Molecular Immunology, Cincinnati Children's Hospital Research Foundation, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
authors.forename: Maria E
authors.initials: ME
authors.lastname: Moreno-Fernandez
authors.forename: Wildeman
authors.initials: W
authors.lastname: Zapata
authors.forename: Jason T
authors.initials: JT
authors.lastname: Blackard
authors.forename: Genoveffa
authors.initials: G
authors.lastname: Franchini
authors.forename: Claire A
authors.initials: CA
authors.lastname: Chougnet
mesh_terms: D004279:DNA, Viral / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D016655:HIV Core Protein p24 / Q000032:analysis; D015497:HIV-1 / Q000145:classification / Q000502:physiology*; D006801:Humans; D008213:Lymphocyte Activation; D019713:Receptors, CCR5 / Q000032:analysis; D019718:Receptors, CXCR4 / Q000032:analysis; D050378:T-Lymphocytes, Regulatory / Q000821:virology*; D014779:Virus Replication
chemical_list: C527276:CXCR4 protein, human; D004279:DNA, Viral; D016655:HIV Core Protein p24; D019713:Receptors, CCR5; D019718:Receptors, CXCR4