Cancer Immunity, Vol. 7, p. 5 (5 March 2007) Submitted: 8 November 2006. Accepted: 4 January 2007.
Shuichiro Sato1,2, Yuji Noguchi1, Nobuya Ohara3, Akiko Uenaka1, Michihide Shimono1, Kazuhiko Nakagawa1, Fumihito Koizumi1, Toshiaki Ishida1, Tadashi Yoshino3, Yasushi Shiratori2 and Eiichi Nakayama1
1Department of Immunology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
2Department of Gastroenterology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
3Department of Pathology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
Contributed by: LJ Old
XAGE-1 is a cancer/testis (CT) antigen and has been shown to be immunogenic in lung cancer patients. Among 4 alternative splicing variants, XAGE-1a, b, c and d, XAGE-1b mRNA was dominantly expressed in cancer. In this study, we generated a XAGE-1b mAb, USO9-13. The B cell epitope recognized by the USO9-13 mAb was in the C-terminal region of the XAGE-1b protein and is also recognized by sera from patients with lung adenocarcinoma. Using USO9-13 and an anti-Flag mAb, we examined the translation products of the 4 transcripts. The XAGE-1a and b transcripts translated to the XAGE-1b protein. The XAGE-1c transcript possibly translated to 9- and 17-aa polypeptides. The XAGE-1d transcript translated to a protein consisting of 69 amino acids. Immunofluorescence analysis using USO9-13 mAb showed that the XAGE-1b protein is located in the nuclei of cells. Immunohistochemically, nuclear staining was heterogeneously observed in 25/47 lung adenocarcinomas, 1/12 hepatocellular carcinomas and 1/11 gastric cancers, but not in adjacent normal tissues. These findings suggested that XAGE-1b is a promising target molecule for a cancer vaccine against lung cancer.
Copyright © 2007 by Shuichiro Sato