title: T-cell signalling in antiretroviral-treated, aviraemic HIV-1-positive individuals is present in a raised state of basal activation that contributes to T-cell hyporesponsiveness.
abstract: OBJECTIVE
  Successful antiretroviral therapy (ART) suppresses plasma HIV-1 RNA below detection limits, reducing the chronic insult to the immune systems of infected individuals and supporting a degree of immunological recovery. However, the surface phenotypic profile of T cells in ART-treated patients does not resemble that of healthy, uninfected individuals, but rather shows upregulation of proteins associated with an exhausted immune system. We sought to address whether aviraemic HIV-1 infection, therefore, contributed to long-term alterations in intracellular signalling events within the T cells of infected individuals that contributed to the exhausted phenotype.
  
  
  METHODS
  A flow cytometric approach was employed to assess levels of phosphorylation within T-cell signalling proteins in ART-treated HIV-1-positive patients and HIV-negative individuals.
  
  
  METHODS
  The relative phosphorylation levels of extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinases (JNK), p38, zeta-chain-associated protein kinase 70 (ZAP70), linker of activated T cells, SLP76, nuclear factor kappaB were measured within resting and stimulated CD4(+) and CD8(+) T cells from aviraemic HIV-1-positive and healthy individuals by intracellular staining and flow cytometric analysis.
  
  
  RESULTS
  Basal levels of phospho-ZAP70, phospho-ERK and phospho-JNK were two-fold to three-fold higher in HIV-1-positive individuals compared with healthy controls, with phospho-p38 also showing a tendency to increase in HIV-1-positive individuals. Interestingly, in contrast to healthy controls, peripheral blood mononuclear cells from aviraemic, infected individuals were refractory to stimulation with IL-2 and CD3/CD28 showing no enhancement of phosphorylation.
  
  
  CONCLUSIONS
  CD4(+) and CD8(+) T cells from HIV-1-positive individuals are poorly responsive to direct stimulation through the T-cell receptor due to chronically raised basal activation levels of intracellular signalling molecules.
authors.affiliation: Section of Immunology, Department of Medicine, Imperial College London, UK. j.downey@imperial.ac.uk
authors.forename: Jocelyn S
authors.initials: JS
authors.lastname: Downey
authors.forename: Meriem
authors.initials: M
authors.lastname: Attaf
authors.forename: Graeme
authors.initials: G
authors.lastname: Moyle
authors.forename: Brian
authors.initials: B
authors.lastname: Gazzard
authors.forename: Frances
authors.initials: F
authors.lastname: Gotch
authors.forename: Nesrina
authors.initials: N
authors.lastname: Imami
mesh_terms: D000328:Adult; D000368:Aged; D019380:Anti-HIV Agents / Q000627:therapeutic use; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000187:drug effects / Q000235:genetics / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D015658:HIV Infections / Q000188:drug therapy / Q000235:genetics / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D010766:Phosphorylation; D015398:Signal Transduction; D015854:Up-Regulation; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents; D048049:Extracellular Signal-Regulated MAP Kinases