title: Lysis of endogenously infected CD4+ T cell blasts by rIL-2 activated autologous natural killer cells from HIV-infected viremic individuals.
abstract: Understanding the cellular mechanisms that ensure an appropriate innate immune response against viral pathogens is an important challenge of biomedical research. In vitro studies have shown that natural killer (NK) cells purified from healthy donors can kill heterologous cell lines or autologous CD4+ T cell blasts exogenously infected with several strains of HIV-1. However, it is not known whether the deleterious effects of high HIV-1 viremia interferes with the NK cell-mediated cytolysis of autologous, endogenously HIV-1-infected CD4+ T cells. Here, we stimulate primary CD4+ T cells, purified ex vivo from HIV-1-infected viremic patients, with PHA and rIL2 (with or without rIL-7). This experimental procedure allows for the significant expansion and isolation of endogenously infected CD4+ T cell blasts detected by intracellular staining of p24 HIV-1 core antigen. We show that, subsequent to the selective down-modulation of MHC class-I (MHC-I) molecules, HIV-1-infected p24(pos) blasts become partially susceptible to lysis by rIL-2-activated NK cells, while uninfected p24(neg) blasts are spared from killing. This NK cell-mediated killing occurs mainly through the NKG2D activation pathway. However, the degree of NK cell cytolytic activity against autologous, endogenously HIV-1-infected CD4+ T cell blasts that down-modulate HLA-A and -B alleles and against heterologous MHC-I(neg) cell lines is particularly low. This phenomenon is associated with the defective surface expression and engagement of natural cytotoxicity receptors (NCRs) and with the high frequency of the anergic CD56(neg)/CD16(pos) subsets of highly dysfunctional NK cells from HIV-1-infected viremic patients. Collectively, our data demonstrate that the chronic viral replication of HIV-1 in infected individuals results in several phenotypic and functional aberrancies that interfere with the NK cell-mediated killing of autologous p24(pos) blasts derived from primary T cells.
authors.affiliation: Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Manuela
authors.initials: M
authors.lastname: Fogli
authors.forename: Domenico
authors.initials: D
authors.lastname: Mavilio
authors.forename: Enrico
authors.initials: E
authors.lastname: Brunetta
authors.forename: Stefania
authors.initials: S
authors.lastname: Varchetta
authors.forename: Khaled
authors.initials: K
authors.lastname: Ata
authors.forename: Gregg
authors.initials: G
authors.lastname: Roby
authors.forename: Colin
authors.initials: C
authors.lastname: Kovacs
authors.forename: Dean
authors.initials: D
authors.lastname: Follmann
authors.forename: Daniela
authors.initials: D
authors.lastname: Pende
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Ward
authors.forename: Edward
authors.initials: E
authors.lastname: Barker
authors.forename: Emanuela
authors.initials: E
authors.lastname: Marcenaro
authors.forename: Alessandro
authors.initials: A
authors.lastname: Moretta
authors.forename: Anthony S
authors.initials: AS
authors.lastname: Fauci
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D049109:Cell Proliferation; D003602:Cytotoxicity, Immunologic; D016655:HIV Core Protein p24 / Q000276:immunology; D015658:HIV Infections / Q000097:blood / Q000276:immunology*; D015234:HLA-A Antigens / Q000378:metabolism; D015235:HLA-B Antigens / Q000378:metabolism; D006801:Humans; D007376:Interleukin-2 / Q000276:immunology*; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D016260:Monocytes, Activated Killer / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D011994:Recombinant Proteins; D014779:Virus Replication
chemical_list: D016655:HIV Core Protein p24; D015234:HLA-A Antigens; D015235:HLA-B Antigens; D007376:Interleukin-2; D011994:Recombinant Proteins