title: IL-2 production correlates with effector cell differentiation in HIV-specific CD8+ T cells.
abstract: BACKGROUND
  Diminished IL-2 production and lack of effector differentiation have been reported for HIV-specific T cells. In this study, we examined the prevalence of these phenomena using 8-color cytokine flow cytometry, and tested the hypothesis that these two findings were causally related. We analyzed cytokine profiles and memory/effector phenotypes of HIV-specific and CMV-specific T cells using short-term in vitro stimulation with HIV or CMV peptide pools. Nineteen HIV-positive subjects with progressive disease and twenty healthy, HIV-negative subjects were examined.
  
  
  RESULTS
  Among HIV-infected subjects, there were significantly fewer CD8+ IL-2+ T cells responding to HIV compared to CMV, with no significant difference in CD4+ IL-2+ T cells. The majority of CMV-specific T cells in both HIV-negative and HIV-positive subjects appeared to be terminally differentiated effector cells (CD8+ CD27- CD28- CD45RA+ or CD8+ CD27- CD28- CD45RA-). In HIV-positive subjects, the most common phenotype of HIV-specific T cells was intermediate in differentiation (CD8+ CD27+ CD28- CD45RA-). These differences were statistically significant, both as absolute cell frequencies and as percentages. There was a significant correlation between the absolute number of HIV-specific CD8+ IL-2+ T cells and HIV-specific CD8+ CD27- CD28- CD45RA+ terminal effector cells.
  
  
  CONCLUSIONS
  IL-2 production from antigen-specific CD8+ T cells correlates with effector cell differentiation of those cells.
authors.affiliation: BD Biosciences, Immunocytometry Systems, 2350 Qume Dr, San Jose, CA 95131, USA. laurel_nomura@bd.com
authors.forename: Laurel E
authors.initials: LE
authors.lastname: Nomura
authors.forename: Brinda
authors.initials: B
authors.lastname: Emu
authors.forename: Rebecca
authors.initials: R
authors.lastname: Hoh
authors.forename: Perry
authors.initials: P
authors.lastname: Haaland
authors.forename: Steven G
authors.initials: SG
authors.lastname: Deeks
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Martin
authors.forename: Joseph M
authors.initials: JM
authors.lastname: McCune
authors.forename: Douglas F
authors.initials: DF
authors.lastname: Nixon
authors.forename: Holden T
authors.initials: HT
authors.lastname: Maecker