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Evaluation of CD8 + T‐cell frequencies by the Elispot assay in healthy individuals and in patients with metastatic melanoma immunized with tyrosinase peptide
Author(s) -
Lewis Jonathan J.,
Janetzki Sylvia,
Schaed Susanne,
Panageas Katherine S.,
Wang Siqun,
Williams Linda,
Meyers Michael,
Butterworth Leah,
Livingston Philip O.,
Chapman Paul B.,
Houghton Alan N.
Publication year - 2000
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/1097-0215(20000801)87:3<391::aid-ijc13>3.0.co;2-k
Subject(s) - elispot , tyrosinase , melanoma , cd8 , medicine , immunology , immunotherapy , cytotoxic t cell , metastatic melanoma , cancer research , biology , antigen , immune system , enzyme , biochemistry , in vitro
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)‐γElispot assay detecting T cells at the single cell level that secrete IFN‐γ. 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. Int. J. Cancer 87:391–398, 2000. © 2000 Wiley‐Liss, Inc.