Abstract: Abstract: Objective To investigate the feasibility of Wilms’tumor gene 1 (WT1)- specific CD8+ T cells from periph⁃ eral blood for the treatment of breast cancer by detecting the killing activity of WT1 specific CD8+ T cells on breast cancer cells. Methods Flow cytometry was used to detect WT1-specific CD8+ T cells in the peripheral blood of 20 samples from HLA-A2 seropositive healthy donors, which were isolated by WT1/MHC streptamer magnetic beads and cultured. The func⁃ tion of WT1-specific CD8+ T cells were analysis by cytotoxicity assay. Results Twelve of 20 healthy donors had naive WT1-specific CD8+ T-cell frequencies of ＞0.5%, and 4 of 20 even ＞1.0% of all CD8+ T cells. After positive selection by magnetic cell separation, a purity of up to 80% can be achieved. WT1 specific CD8+ T cells can specifically kill breast can⁃ cer cell line with WT1 polypeptide. Conclusion WT1 specific CD8+ T cells can be detected in peripheral blood of healthy volunteers. WT1 specific CD8+ T cells have killing effect on breast cancer cells, suggesting the feasibility of adoptive immu⁃ notherapy for breast cancer.

Key words: breast neoplasms, immunotherapy, adoptive, CD8-positive T-lymphocytes, Wilms’tumor gene 1, cell immunotherapy