title: Measuring inhibition of HIV replication by ex vivo CD8⁺ T cells.
abstract: HIV replication is unrestrained in vivo in the vast majority of infected subjects, and the ability of some rare individuals to control this virus is poorly understood. Standard immunogenicity assays for detecting HIV-1-specific CD8(+) T-cell responses, such as IFN-γ ELISpot and intracellular cytokine staining, generally fail to correlate with in vivo inhibition of HIV replication. Several viral inhibition assays, which measure the effectiveness of CD8(+) T-cell responses in suppressing HIV replication in vitro, have been described; but most depend on in vitro expansion of CD8(+) T cells, and some show inhibitory activity in HIV-negative individuals. We have optimized an assay to assess the suppressive capability of CD8(+) T cells directly ex vivo, eliminating the potential for altering their function through activation or expansion prior to assay setup, and thereby enhancing the assay's sensitivity by avoiding non-specific inhibition. With this method, the ability of ex vivo CD8(+) T cells to control HIV-1 replication in vitro can be quantified over several orders of magnitude. Specifically, our assay can be used to better define the antiviral function of CD8(+) T cells induced by vaccination, and can provide insight into their ability to control viral replication if HIV infection occurs post-vaccination.
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States.
authors.forename: Chloe K
authors.initials: CK
authors.lastname: Slichter
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States.
authors.forename: David P
authors.initials: DP
authors.lastname: Friedrich
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Smith
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States.
authors.forename: Paula N
authors.initials: PN
authors.lastname: Walsh
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States.
authors.forename: Greg
authors.initials: G
authors.lastname: Mize
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States.
authors.forename: Julie L
authors.initials: JL
authors.lastname: Czartoski
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States; Department of Global Health, University of Washington, Seattle, WA, United States; Department of Medicine, University of Washington, Seattle, WA, United States; Department of Laboratory Medicine, University of Washington, Seattle, WA, United States.
authors.forename: M Juliana
authors.initials: MJ
authors.lastname: McElrath
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States; Department of Global Health, University of Washington, Seattle, WA, United States. Electronic address: nfrahm@fhcrc.org.
authors.forename: Nicole
authors.initials: N
authors.lastname: Frahm
mesh_terms: D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000473:pathology / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000473:pathology / Q000821:virology; D005260:Female; D017930:Genes, Reporter; D016655:HIV Core Protein p24 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D015658:HIV Infections / Q000276:immunology* / Q000473:pathology / Q000821:virology; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007118:Immunoassay; D008156:Luciferases / Q000235:genetics; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D061251:Primary Cell Culture; D012680:Sensitivity and Specificity; D014779:Virus Replication / Q000276:immunology*
chemical_list: D016655:HIV Core Protein p24; D008156:Luciferases
keywords: CD8 T cells; HIV suppression; Vaccine-induced T-cell responses; Viral inhibition