title: Immune responses to p53 in patients with cancer: enrichment in tetramer+ p53 peptide-specific T cells and regulatory T cells at tumor sites.
abstract: OBJECTIVE
  A majority of human cancers, including head and neck cancer (HNC), "overexpress" p53. Although T cells specific for wild-type (wt) sequence p53 peptides are detectable in the peripheral blood of patients with HNC, it is unknown whether such T cells accumulate in tumor-involved tissues. Also, the localization of "regulatory" T cells (Treg) to tumor sites in HNC has not been investigated to date.
  
  
  METHODS
  Tumor infiltrating lymphocytes (TIL), tumor-involved or non-involved lymph node lymphocytes (LNL) and peripheral blood mononuclear cells (PBMC) were obtained from 24 HLA-A2.1+ patients with HNC. Using tetramers and four-color flow cytometry, the frequency of Treg and CD3+CD8+ T cells specific for wt p53 epitopes as well as their functional attributes were determined.
  
  
  RESULTS
  The CD3+CD8+ tetramer+ cell frequency was significantly higher (P<0.001) in TIL than autologous PBMC as was the percentage of CD4+CD25+ T cells (P<0.003). TIL were enriched in FOXp3+, GITR+ and CTLA-4+ Treg. CD8+ TIL had low Zeta expression and produced little IFN-gamma after ex vivo stimulation relative to autologous PBMC or PBMC from NC.
  
  
  CONCLUSIONS
  Anti-wt p53 epitope-specific T cells and Treg preferentially localize to tumor sites in patients with HNC. However, despite enrichment in tumor peptide-specific T cells, the effector cell population (CD3+CD8+) in TIL or PBMC was unresponsive to activation in the tumor microenvironment enriched in Treg.
authors.affiliation: University of Pittsburgh Cancer Institute and Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: Andreas E
authors.initials: AE
authors.lastname: Albers
authors.forename: Robert L
authors.initials: RL
authors.lastname: Ferris
authors.forename: Grace G
authors.initials: GG
authors.lastname: Kim
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Chikamatsu
authors.forename: Albert B
authors.initials: AB
authors.lastname: DeLeo
authors.forename: Theresa L
authors.initials: TL
authors.lastname: Whiteside
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002294:Carcinoma, Squamous Cell / Q000276:immunology*; D004268:DNA-Binding Proteins / Q000032:analysis; D005260:Female; D051858:Forkhead Transcription Factors; D053450:Glucocorticoid-Induced TNFR-Related Protein; D006258:Head and Neck Neoplasms / Q000276:immunology*; D006801:Humans; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D017475:Receptors, Nerve Growth Factor / Q000032:analysis; D018124:Receptors, Tumor Necrosis Factor / Q000032:analysis; D013601:T-Lymphocytes / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology; D016159:Tumor Suppressor Protein p53 / Q000276:immunology*
chemical_list: D004268:DNA-Binding Proteins; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D053450:Glucocorticoid-Induced TNFR-Related Protein; D017475:Receptors, Nerve Growth Factor; D018124:Receptors, Tumor Necrosis Factor; C491405:TNFRSF18 protein, human; D016159:Tumor Suppressor Protein p53