title: Evaluation of CD8(+) T-cell frequencies by the Elispot assay in healthy individuals and in patients with metastatic melanoma immunized with tyrosinase peptide.
abstract: The lack of reproducible, quantitative assays for T-cell responses has been a limitation in the development of cancer vaccines to elicit T-cell immunity. We utilized the Elispot assay, which allows a quantitative and functional assessment of T cells directed against specific peptides after only brief in vitro incubations. CD8(+) T-cell reactivity was determined with an interferon (IFN)-gamma Elispot assay detecting T cells at the single cell level that secrete IFN-gamma. We studied both healthy individuals and patients with melanoma. Healthy HLA-A*0201-positive individuals showed a similar mean frequency of CD8(+) cells recognizing a tyrosinase peptide, YMDGTMSQV, when compared with melanoma patients prior to immunization. The frequencies of CD8(+) cells recognizing the tyrosinase peptide remained relatively constant over time in healthy individuals. Nine HLA-A*0201-positive patients with stage IV metastatic melanoma were immunized intradermally with the tyrosinase peptide together with the immune adjuvant QS-21 in a peptide dose escalation study with 3 patients per dose group. Two patients demonstrated a significant increase in the frequency of CD8(+) cells recognizing the tyrosinase peptide during the course of immunization, from approx. 1/16,000 CD8(+) T cells to approx. 1/4,000 in the first patient and from approx. 1/14,000 to approx. 1/2,000 in the second patient. These results demonstrate that modest expansion of peptide-specific CD8(+) T cells can be generated in vivo by immunization with peptide plus QS-21 in at least a subset of patients with melanoma.
authors.affiliation: Swim Across America Laboratory, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA. lewisj@mskcc.org
authors.forename: J J
authors.initials: JJ
authors.lastname: Lewis
authors.forename: S
authors.initials: S
authors.lastname: Janetzki
authors.forename: S
authors.initials: S
authors.lastname: Schaed
authors.forename: K S
authors.initials: KS
authors.lastname: Panageas
authors.forename: S
authors.initials: S
authors.lastname: Wang
authors.forename: L
authors.initials: L
authors.lastname: Williams
authors.forename: M
authors.initials: M
authors.lastname: Meyers
authors.forename: L
authors.initials: L
authors.lastname: Butterworth
authors.forename: P O
authors.initials: PO
authors.lastname: Livingston
authors.forename: P B
authors.initials: PB
authors.lastname: Chapman
authors.forename: A N
authors.initials: AN
authors.lastname: Houghton
mesh_terms: D000328:Adult; D001324:Autoantigens / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes; D019496:Cancer Vaccines / Q000627:therapeutic use*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015789:HLA-A2 Antigen / Q000276:immunology; D006801:Humans; D016233:Immunotherapy, Active; D018655:Lymphocyte Count; D008297:Male; D008545:Melanoma / Q000276:immunology* / Q000473:pathology / Q000628:therapy; D008875:Middle Aged; D014442:Monophenol Monooxygenase / Q000276:immunology*; D009362:Neoplasm Metastasis; D009363:Neoplasm Proteins / Q000276:immunology*; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000276:immunology; D010865:Pilot Projects; D012016:Reference Values
chemical_list: D001324:Autoantigens; D019496:Cancer Vaccines; D015789:HLA-A2 Antigen; D009363:Neoplasm Proteins; D010446:Peptide Fragments; D014442:Monophenol Monooxygenase