Generation of cytotoxic T cell responses to an HLA-A24 restricted epitope peptide derived from wild-type p53.

Mutations in the p53 gene are the most common genetic alterations found in human tumours, and these mutations result in high levels of p53 protein in the tumour cells. Since the expression levels of wild-type p53 in nonmalignant tissue are usually much lower in contrast, the p53 protein is an attractive target for cancer immunotherapy. We tested p53 encoded HLA-A24 binding peptides for their capacity to elicit anti-tumour cytotoxic T lymphocytes (CTL) in vitro. These peptides were in murine p53-derived cytotoxic peptides, which were being presented to CTL by H-2K(d)and H-2K(b)molecules, because the HLA-A24 peptide binding motifs were similar to the H-2K(d)and H-2K(b). For CTL induction, we used CD8(+)T lymphocytes from the peripheral blood mononuclear cells (PBMC) of healthy donors and the peptides from pulsed dendritic cells as antigen-presenting cells. We identified the peptide, p53-161 (AIYKQSQHM), which was capable of eliciting CTL lines that lysed tumour cells expressing HLA-A24 and p53. The effectors lysed C1RA24 cells (p53(+), HLA-A*2402 transfectant), but not their parental cell lines C1R (p53(+), HLA-A,B null cell). These results strongly indicate that the CTL exerts cytotoxic activity in HLA-A24's restricted manner. The identification of this novel p53 epitope for CTL offers the possibility to design and develop specific immunotherapeutic approaches for treating tumours with p53 mutation in HLA-A24-positive patients.

Mapping the HLA-A24-restricted T-cell epitope peptide from a tumour-associated antigen HER2 / neu: possible immunotherapy for colorectal carcinomas.

HER2 / neu is a potential antigen candidate for immunotherapy because of its correlation to a poor prognosis and high expressions in many kinds of epithelial tumours. Especially in the colorectal carcinomas, the higher expression of HER2 / neu is recognized in metastatic regions as well as in primary sites. Several CTL epitopes restricted by HLA-A2.1 and -A3 were identified so far, however epitopes restricted by HLA-A24, that is one of the most common allele in Japanese and Caucasians, have not been identified. In this paper, we showed identification of a CTL epitope peptide of HER2 / neu restricted by HLA-A24. HLA-A24 binding peptides selected by an analysis based on HLA-A24 binding motifs were determined for their binding affinities to HLA-A24 molecules. The peptide with a sequence of RWGLLLALL (position 8-16) named HE1 showed the highest affinity. We induced CTLs from CD8(+)cells of HLA-A24 healthy donors by stimulation with HE1-pulsed autologous dendritic cells. The CTLs showed cytotoxic activity against not only the peptide-pulsed target cells but also HLA-A24 colorectal tumour cell lines that endogenously overexpressed HER2 / neu. The antigen-specificity was confirmed by cold target inhibition assay using HE1-pulsed target cells. In summary, HER2 / neu peptide, RWGLLLALL, may contribute to the induction of antitumour immunity with the peptide-based immunotherapy for the colorectal carcinomas.

Hepatic actinomycosis infiltrating the diaphragm and right lung.

Hepatic actinomycosis is a rare infectious disease caused by an anaerobic gram-positive bacterium of the genus Actinomyces. Herein, we describe an unusual case of hepatic actinomycosis involving the diaphragm and right lung. A 41-yr-old man was admitted to Wakayama Medical School Hospital presenting with right back pain and cough. Computed tomography and magnetic resonance image revealed a 5 x 10 cm tumor in the anterior superior segment of the liver, which extended to the diaphragm and right lung. Angiography demonstrated a hypervascular tumor and the enlarged right inferior phrenic artery feeding around the tumor. The patient underwent a hepatectomy with partial resections of the diaphragm and the right middle pulmonary lobe. Microscopically, the specimen showed sulfur granules and was positive for Gram stain and Grocott stain and negative for Ziehl-Neelsen stain. These findings were consistent with actinomycosis of the liver. His postoperative course was uneventful and no recurrence was observed 1 yr postoperatively. Although there are at least 36 well-documented cases until 1993, no other report has been found infiltrating the diaphragm and lung.