Bladder carcinoma is the fourth most common cancer in men and the eighth most common cancer among women. Our study is aimed to characterise tumour-associated antigen peptides of transitional cell carcinoma of the bladder (TCC). A DNA micro-array-based differential display analysis of 10 000 genes was carried out, and MAGE-A8 gene expression was detected in the tumour, and not in the normal bladder. High occurrence of MAGE-A8 expression was observed in fresh tumour samples (17 out of 23) and TCC lines (four of eight). The MAGE-A8 protein sequence was screened for HLA-A2.1-binding motifs, six potential peptides were synthesised, and peptides binding to HLA-A2.1 were assured. Immunogenicity and antigenicity of the MAGE-A8 peptides were examined in the HHD system, murine class I MHC knockout mice, transgenic for HLA-A2.1. The MAGE-A8 peptide immunogenicity was examined in three modes of vaccination, delivered intranasally with cholera toxin, injected into the tail base with complete Freund's adjuvant (CFA), or presented directly as loaded onto cell surface HLA-A2.1 molecules. Two peptides, 8.1 and 8.3, induce CTL that kills the T24 TCC line in vivo, and prime human lymphocyte response of healthy donors. These results demonstrate the potential use of the MAGE-A8 peptides for specific immunotherapy of TCC.
Bibliographical noteFunding Information:
The skilful technical assistance of Mrs S Rubinraut in peptide synthesis is greatly appreciated. This study was supported by grants from the Minerva foundation, the ICRF and the Sternberg family foundation. LE is the incumbent of the George F Duckwitz chair of cancer research.