ANALYSIS OF THE T-CELL RESPONSE TO TUMOR AND VIRAL PEPTIDE ANTIGENS BY AN IFN-GAMMA-ELISPOT ASSAY

We have established a sensitive ELISPOT assay measuring interferon gam ma (IFN gamma) release on a single-cell basis to detect influenza pept ide-specific CD8(+) T cells in uncultured peripheral blood mononuclear cells (PBMC). Using this method, we studied the T cell response to HL A-A1 and HLA-A2.1 binding peptide epitopes derived from the MAGE-1 and MAGE-3 proteins, from the melanoma-associated antigens tyrosinase, Me lan-A/MART-1 and gp100, and from influenza proteins in stage IV melano ma patients and healthy controls. In 18 of 24 HLA-A2-positive donors ( 75%), but only in 9 of 25 HLA-A2-positive melanoma patients (36%)T cel ls reactive with the influenza matrix peptide were demonstrated (p = 0 .007). T cells responding to one or several of the melanoma-associated peptides were detected in 5 of 25 HLA-A2-positive patients with metas tatic melanoma. Four of these 5 patients had been treated with interle ukin-2- and IFN alpha-containing therapy. Two of the 24 healthy donors had T cells reactive with the MART-1 27-35 peptide. No reactivity wit h the HLA-A1-binding peptides from MAGE-1 or MAGE-3 was detected in an y of the HLA-A1-positive healthy controls or melanoma patients, These results show that the IFN gamma-ELISPOT assay is suitable to determine quantitatively T cells reactive with melanoma-associated and influenz a peptide epitopes in uncultured PBMC. The failure to detect T cells r esponding to influenza in many melanoma patients with progressive dise ase may indicate an impairment of their T cell function. (C) 1997 Wile y-Liss, Inc.