The CD4+ T-Cell Response of Melanoma Patients to a MAGE-A3 Peptide Vaccine Involves Potential Regulatory T Cells

摘要: Melanoma patients were injected with various vaccines containing a MAGE-A3 peptide presented by HLA-DP4. Anti-MAGE-A3.DP4 T cells not detectable in the blood before vaccination, but their frequencies after vaccination ranged from 2 x 10(-6) to 10(-3) among CD4(+) lymphocytes of patients. The that stained ex vivo HLA-DP4 tetramers folded selected flow cytometry and amplified under clonal conditions. About 5% T-cell clones recognized MAGE-A3.DP4 antigen had CD25(+) phenotype resting state. These high capacity suppress proliferation another clone stimulation vitro. Most them FOXP3 expression state an unmethylated intron 1. They produced active transforming growth factor-beta none cytokines IFN-gamma, interleukin-2 (IL-2), IL-4, IL-5, IL-10. 20% CD25(-) significant lower suppressive activity. populations contained expressed state, demethylation was observed. We conclude can produce may exert regulatory function vivo.