Kazuko Matsunaga

Identification of a Gene Coding for a New Squamous Cell Carcinoma Antigen Recognized by the CTL

Peptide-based specific immunotherapy has resulted in tumor regression in some melanoma patients. However, tumor Ags and peptides for specific immunotherapy, except for treatment of melanomas, have not yet been well identified. In this study, we report a gene encoding a new squamous cell carcinoma (SCC) Ag recognized by cells of the HLA-A24-restricted and tumor-specific CTL line. This gene with 3958-bp length was transcribed from the chromosome 6q22 with six exons, and its mRNA was ubiquitously expressed in both SCCs and normal tissues, and partly expressed in adenocarcinomas. The deduced 958-aa sequence encoded by this gene showed no similarity to any known amino acid sequences. This gene product had a characteristic of an endoplasmic reticulum-resident protein. A 100-kDa protein was detected in the vast majority of SCCs from various tissues, in majority of renal cell carcinomas and brain tumors, and in about one-third of melanomas and adenocarcinomas from various organs other than the breast. In contrast, it was not expressed at all in any of the normal cells or tissues tested, including the testis and fetal liver. Three different peptides at positions 93–101, 161–169, and 899–907 of this Ag were recognized by this CTL line, and all of them induced HLA-A24-restricted and tumor-specific CTLs from PBMCs of SCC patients. Therefore, these peptides may be useful for peptide-based specific immunotherapy of HLA-A24+ patients with SCC in various organs, as well as for treatment of other cancer.

Identification of a SART‐1‐derived peptide capable of inducing HLA‐A24‐restricted and tumor‐specific cytotoxic T lymphocytes

We have described the SART‐1 gene–encoding peptides recognized by HLA‐A2601‐restricted and tumor‐specific cytotoxic T lymphocytes (CTLs). We now have investigated whether SART‐1 encodes peptides capable of inducing the HLA‐A24‐restricted CTLs. Among the 18 different peptides with HLA‐A24‐binding motifs, the SART‐1690–698 peptide (EYRGFTQDF) was most strongly recognized by the HLA‐A24‐restricted and tumor‐specific CTLs established from an esophageal cancer patient. After a third stimulation in vitro, this peptide induced HLA‐A24‐restricted CTLs recognizing the SART‐1259+ tumor cells in PBMCs of all HLA‐A24 homozygous and the majority of HLA‐A24 heterozygous cancer patients and healthy donors tested. A similar activity, induction of CTLs from PBMCs, was observed in the Saccharomyces cerevisiae–derived nonapeptide (EYRGFTPMF) that shares 7 amino acids with the SART‐1690–698 peptide. The SART‐1690–698 peptide–induced CTL activity was significantly higher in PBMCs of HLA‐A24 homozygotes than in HLA‐A24 heterozygotes. The CTL precursor frequency in PBMCs after a third stimulation in vitro with the SART‐1690–698 peptide was high (>1/200) in both cancer patients and healthy donors. The SART‐1690–698 peptide could thus be useful for specific immunotherapy of HLA‐A24+ cancer patients. Int. J. Cancer 81:459–466, 1999.

Expression of the SART3 tumor-rejection antigen in brain tumors and induction of cytotoxic T lymphocytes by its peptides.

The authors recently reported on the SART3 tumor-rejection antigen, which possesses epitopes that can induce cytotoxic T lymphocytes (CTLs) in patients with epithelial cancer. To explore a new modality for treatment of patients with brain tumors, this study investigated the expression of the SART3 antigen in patients with brain tumors and the ability of SART3 peptides to induce CTLs from peripheral blood mononuclear cells (PBMCs) of these patients. The SART3 antigen was detected in the cytoplasmic fraction of all 18 glioma cell lines examined and in the majority (31 of 34; 91%) of brain tumor tissues irrespective of their histologies. It was also expressed in the nuclear fraction of all 18 glioma cell lines and in the majority (26 of 34; 76%) of brain tumor tissues. In contrast, the SART3 was not expressed in nontumorous brain tissues. Cytotoxic T lymphocytes were induced in patients with glioma by stimulation with two epitope peptides of SART3. These CTLs could eliminate glioma cells in a HLA-A24–restricted manner. Therefore, the SART3 peptides may be appropriate molecules for use in peptide-based specific immunotherapy of HLA-A24+ patients with brain tumors.

Expression of the tumor-rejection antigen SART1 in brain tumors.

We have reported a tumor‐rejection antigen, SART1259, possessing tumor epitopes capable of inducing cytotoxic T lymphocytes (CTLs) in epithelial‐cancer patients. This study investigated the expression of SART1259 antigen in brain tumors, to explore for a potential molecule for use in specific immunotherapy of patients with brain tumors. The SART1259 antigen was detected in the cytosol fraction of 13 of 18 (72%) glioma cell lines and in 12 of 34 (35%) brain‐tumor tissues, with a higher rate of expression among malignant gliomas (5/10, 50%) and schwannomas (3/4). HLA‐A24‐restricted and SART1‐specific CTLs recognized the HLA‐A24+ and SART1259+ glioma cells, and the levels of recognition correlated both with HLA‐A24‐antigen expression level and with the concentration of the SART1 peptide antigen. Therefore, the SART1259 antigen could be a target molecule for specific immunotherapy of patients with brain tumors expressing HLA‐class‐I antigens. Int. J. Cancer 83:760–764, 1999.

Expression of tumor rejection antigens in colorectal carcinomas

The authors recently reported that the SART2 and SART3 antigens encode tumor epitopes recognized by HLA‐A24‐restricted and tumor‐specific cytotoxic T lymphocytes (CTLs) established from esophageal carcinoma patients. The current study investigated these antigens to explore a potential molecule for specific immunotherapy for colorectal carcinoma patients.

Phase 1 clinical study of cyclophilin B peptide vaccine for patients with lung cancer.

Cyclophilin B (CypB) possesses two antigenic epitopes (CypB84–92 and CypB91–99) recognized by HLA-A24-restricted and tumor-specific cytotoxic T lymphocytes (CTLs). To determine the safety of CypB-derived peptides and its ability to generate antitumor immune responses, patients with advanced lung cancer received subcutaneous vaccinations of these peptides or their modified peptides. All 16 patients were vaccinated with CypB91–99 or its modified peptide, whereas only two patients were vaccinated with the modified CypB84–92, as immediate-type hypersensitivity to CypB84–92 or its modified peptide was observed in the remaining patients. No severe adverse events were associated with the vaccination. No significant increase in cellular responses to either peptides or tumor cells was observed in the postvaccination PBMCs by the conventional CTL assays in any patients tested. These results suggest that the vaccination of CypB91–99 peptide was safe, but failed to induce objective immune responses at this regimen.

Depression, but not sleep disorder, is an independent factor affecting exacerbations and hospitalization in patients with chronic obstructive pulmonary disease.

Background and objective:  Patients with chronic obstructive pulmonary disease (COPD) may experience depression and sleep disorders, which can adversely affect their health‐related quality of life (HRQOL). The aim of this study was to investigate depression and sleep disorders among 85 COPD patients and 46 control subjects, aged 40 years and over.

Overexpression of Chitinase 3-Like 1/YKL-40 in Lung-Specific IL-18-Transgenic Mice, Smokers and COPD

We analyzed the lung mRNA expression profiles of a murine model of COPD developed using a lung-specific IL-18-transgenic mouse. In this transgenic mouse, the expression of 608 genes was found to vary more than 2-fold in comparison with control WT mice, and was clustered into 4 groups. The expression of 140 genes was constitutively increased at all ages, 215 genes increased gradually with aging, 171 genes decreased gradually with aging, and 82 genes decreased temporarily at 9 weeks of age. Interestingly, the levels of mRNA for the chitinase-related genes chitinase 3-like 1 (Chi3l1), Chi3l3, and acidic mammalian chitinase (AMCase) were significantly higher in the lungs of transgenic mice than in control mice. The level of Chi3l1 protein increased significantly with aging in the lungs and sera of IL-18 transgenic, but not WT mice. Previous studies have suggested Chi3l3 and AMCase are IL-13-driven chitinase-like proteins. However, IL-13 gene deletion did not reduce the level of Chi3l1 protein in the lungs of IL-18 transgenic mice. Based on our murine model gene expression data, we analyzed the protein level of YKL-40, the human homolog of Chi3l1, in sera of smokers and COPD patients. Sixteen COPD patients had undergone high resolution computed tomography (HRCT) examination. Emphysema was assessed by using a density mask with a cutoff of −950 Hounsfield units to calculate the low-attenuation area percentage (LAA%). We observed significantly higher serum levels in samples from 28 smokers and 45 COPD patients compared to 30 non-smokers. In COPD patients, there was a significant negative correlation between serum level of YKL-40 and %FEV1. Moreover, there was a significant positive correlation between the serum levels of YKL-40 and LAA% in COPD patients. Thus our results suggest that chitinase-related genes may play an important role in establishing pulmonary inflammation and emphysematous changes in smokers and COPD patients.

Expression of a newly defined tumor-rejection antigen SART3 in musculoskeletal tumors and induction of HLA class I-restricted cytotoxic T lymphocytes by SART3-derived peptides.

We recently reported that a SART3 tumor‐rejection antigen possessing tumor epitopes is capable of inducing HLA class I‐restricted and tumor‐specific cytotoxic T lymphocytes in cancer patients. We studied the expression of the SART3 protein in musculoskeletal tumors to find a molecule for potential use in tumor‐specific immunotherapy. The SART3 was detected at protein levels in 100% of the osteosarcoma cell lines (n = 20), in 50% of the musculoskeletal tumor tissue specimens (n = 32), and at notable levels in 67% of osteosarcoma tissues (n = 9) and malignant fibrous histiocytosis tissues (n = 9), respectively. SART3‐derived peptides at positions 109‐118 and 315‐323 induced HLA‐A24‐restricted tumor‐specific cytoxic T lymphocytes from peripheral blood mononuclear cells of patients with osteosarcoma or malignant fibrous histiocytosis. These peptide‐induced cytotoxic T lymphocytes recognized HLA‐A24+ SART3+ osteosarcoma cells but not HLA‐A24− or SART3− cells. These results suggest that the SART3 protein and its derived peptides could be molecules appropriate for use in specific immunotherapies for approximately 60% of HLA‐A24+ patients with osteosarcoma or malignant fibrous histiocytosis.

Soluble interleukin-18 receptor complex is a novel biomarker in rheumatoid arthritis

IntroductionThere has been no report in the literature of a soluble form of interleukin (IL)-18 receptor α (IL-18Rα). In this study, we evaluated the levels and characteristics of soluble IL-18Rα (sIL-18Rα) in the sera of patients with rheumatoid arthritis (RA) and compared these results to control populations.MethodsThe sIL-18Rα complex was isolated from pooled human blood serum using an anti-IL-18Rα monoclonal antibody affinity column. The purified sIL-18Rα was then examined using Western blot analysis and used in experiments to evaluate the effects on an IL-18-responsive natural killer (NK) human cell line, NK0. An enzyme-linked immunosorbent assay was developed, and sera from 145 patients with RA, 6 patients with adult-onset Stills disease, 31 patients with osteoarthritis (OA), 39 patients with systemic lupus erythematosus (SLE) and 67 controls were tested, along with levels of immunoglobulin M, rheumatoid factor, anticyclic citrullinated peptide antibody, IL-18, IL-13 and interferon (IFN)-γ. Area under the receiver operating characteristic curve (ROC-AUC) analysis was used to evaluate the diagnostic utility of the sIL-18Rα complex.ResultsThe isolated sIL-18Rα complex can be associated with IL-18 and the soluble form of the IL-18Rβ chain. The sIL-18Rα complex bound to the surface to the NK0 cell line, antagonized the stimulatory effects of IL-18 and IL-2 on the NK0 cell line and inhibited IFN-γ production by the cells. The serum levels of sIL-18Rα complex in RA (186.0 ± 33.5 ng/mL, n = 145) and adult-onset Stills disease (98.2 ± 8.9 ng/mL, n = 6) were significantly (P < 0.001) higher than those in the healthy controls (52.3 ± 8.5 ng/mL, n = 67), OA (38.6 ± 5.4 ng/mL, n = 31), SLE (44.6 ± 3.2 ng/mL, n = 39). The serum level of sIL-18Rα complex was not significantly different between RA and adult-onset Stills disease patients. The serum levels of IL-18, IL-13 and IFN-γ in the RA patients were significantly (P < 0.01) higher than in OA and SLE patients as well as healthy controls. ROC-AUC analysis of the serum concentration of sIL-18Rα indicated that it was significantly diagnostic of RA. Moreover, a tumor necrosis factor inhibitor, etanercept, significantly (P < 0.0001) decreased levels of sIL-18Rα in the sera of 29 RA patients 6 months after treatment.ConclusionsThe sIL-18Rα complex could be a potentially useful biomarker for the diagnosis of RA.