Biomedical subjects

Koji Ohta

Publications and source records attributed to Koji Ohta.

22 records · Page 2Linked to original sources

PubMed2003

[Weekly docetaxel therapy is useful for gastric carcinoma as a second-line chemotherapy].

In the present study, we demonstrate the results of weekly administered docetaxel treatments as a second-line chemotherapy after TS-1 treatment in 4 gastric cancer patients. Twenty-five mg/m2 of docetaxel was administered once a week for 3 weeks followed by a 1-week rest period as one cycle. The treatment was continued for 2 to 16 weeks. In case 1, a 60% reduction of the primary tumor was observed for 20 weeks. In cases 2 and 3, the decrease of tumor marker was observed. In one case, progression of the tumor was observed and the treatment was not performed. As for adverse effects, no hematological toxicity was observed; however, in one case, grade 2 hair loss, pleural effusion and grade 2 nail changes were observed. These results indicate that the weekly docetaxel therapy is useful for gastric carcinoma patients, as it reduces the hematologic toxicities and improves the quality of life of the patients in the outpatient setting.

Aged↗

PubMedDate not supplied

Analysis of T cell receptors reactive with squamous cell carcinoma antigen SART-1 presented by the HLA-A24 molecule.

We investigated the induction of cytotoxic T lymphocytes (CTLs) specific for squamous cell carcinoma antigen SART-1 from the peripheral blood mononuclear cells (PBMCs) of an HLA-A24 healthy donor by in vitro stimulation with dendritic cells (DCs) pulsed with the antigenic peptide. Effector cells, designated as cells, exhibited potent cytotoxic activity against target cells in a SART-1-specific and HLA-restricted manner. T cell receptor (TCR) gene usage of the SART-1 PDAK cells analyzed by reverse transcribed-polymerase chain reaction (RT-PCR) and Southern blot analysis showed oligoclonal usage, including TCRVbeta18, which was indicated by blocking assay to be responsible for antigen recognition and killing. Single strand conformation polymorphism (SSCP) analysis revealed clonotypic bands of the TCRVbeta18. The PCR product of the TCRVbeta18 was sequenced and complementarity determining region (CDR) 3 was determined. RT-PCR analysis using this CDR3 sequence as a primer showed, as expected, a positive band of about 30 bp smaller than shown on regular PCR analysis. This clonotypic PCR demonstrated an increasing density of PCR bands in the SART-1 PDAK cells during stimulation with SART-1 peptide plus DCs. It is suggested that clonotypic PCR using the TCR-CDR3 sequence may be useful in assessing the precursor frequency of CTLs reactive with the SART-1 peptide in vivo.

Antigens, Neoplasm↗

PubMedDate not supplied

Novel system for generating cytotoxic effector lymphocytes using carcinoembryonic antigen (CEA) peptide and cultured dendritic cells.

We have established a practical system for generating antitumor effector lymphocytes using the tumor antigen peptide CEA and cultured dendritic cells (DCs), and have also characterized effector cells. DCs were induced from the adherent cell population of autologous peripheral blood mononuclear cells (PBMCs) obtained from HLA-A0201 normal or tumor-bearing donors using IL-4 and GM-CSF. The cultured DCs were shown to express class I, class II, CD80 and CD86 molecules. The PBMCs were stimulated for 7 days with the DCs pulsed with the HLA-A0201-restricted CEA peptide CEA9 671 and then expanded in an anti-CD3 antibody (1 microgram/ml)-coated flask in the presence of a 80 U/ml IL-2 (IL-2/CD3 system). The effector cells, which were designated as CEA peptide-pulsed dendritic cell-activated killer (CEA-PDAK) cells, were preferentially CD3+CD8+, and capable of killing T2 cells pulsed with CEA peptide but not T2 cells alone. The CA-PDAK cells also lysed the gastric cancer cell line KATO III (HLA-A0201, CEA (+)), but not the WiDr (HLA-A2402, CEA(+)) cells. The cytotoxicity was abrogated when the CEA-PDAK cells were treated with anti-TCR alpha beta antibody or when the target cells were treated with the anti-class I antibody prior to the cytotoxicity assay. The CEA-PDAK cells exerted their cytotoxic activity even in the presence of a high amount of CEA protein at the effector phase, which mimicked the clinical setting. The CEA-PDAK cells showed approximately a hundred-fold expansion in total cell numbers yielded without any loss of the specific lysis, when stimulated with the IL-2/CD3 system compared to those stimulated with IL-2 alone. The TCR V beta gene analysis for the CEA-PDAK cells, conducted by means of RT-PCR-Southern blotting, demonstrated oligoclonal expression of TCR beta 7 and 12, and the latter was shown to be responsible for the killing activity. SSCP analysis indicated the clonotype of the TCR V beta 12 gene, indicating a selective expansion of lymphocytes bearing a limited TCR variable region by the stimulation with CEA peptide-pulsed DCs. Taken together, the effector lymphocytes reactive with the CEA antigen can be generated from PBMCs with the antigenic CEA peptide and cultured DCs. The IL-2/CD3 system is effective and practical in activating the effector cells for the clinical use of CEA-PDAK cells. Adoptive immunotherapy using this system may be promising for treating CEA-expressing tumors.

Carcinoembryonic Antigen↗

PubMedDate not supplied

Feasibility study of adoptive immunotherapy for metastatic lung tumors using peptide-pulsed dendritic cell-activated killer (PDAK) cells.

We have established a novel culture system to generate effector lymphocytes designated as peptide-pulsed dendritic cell-activated killer (PDAK) cells using cultured dendritic cells (DCs), synthetic peptide, peripheral blood lymphocytes, and interleukin-2 plus immobilized anti-CD3 antibody. A feasibility study of an adoptive immunotherapy trial using PDAK cells was conducted on HLA-A2 and HLA-A24 cancer patients with antigen-positive lung metastasis that was defined by serological analysis or PCR analysis. Eleven patients with lung metastasis participated in the study: 6 with colorectal cancer, 2 with pancreatic cancer, 1 each with breast and lung cancer, and 1 with melanoma. The patients received either Muc-1, CEA, gpl00, Her-2 or SART-3-PDAK cells generated in vitro, intravenously in combination with 350,000 U IL-2 weekly for 9 weeks, together with a planned dose-escalation schedule of three transfers each of 1 x 10(7), 3 x 10(7) and 1 x 10(8) PDAK cells/kg for 6 patients, and with a uniform dose of 3 x 10(7) PDAK cells/kg for the remaining 5 patients. Peptide/HLA-specific cytotoxic activity and TCRVbeta gene usage of PDAK cells were analyzed. All transfers of PDAK cells, which showed peptide/HLA-specific lysis, were well-tolerated in all patients, and adverse effects (elevation of transaminase, fever, and headache) were observed primarily at grade 1, but in no case greater than grade 2. The generation of sufficient cells to treat the patients with 3 x 10(7) PDAK cells/kg was feasible using our culture system, but we were able to generate and administer the dose of 1 x 10(8) PDAK cells/kg in only one patient. One partial response (PR) of lung metastasis occurred in a pancreatic cancer patient who received 3 x 10(7) Muc-1-PDAK cells/kg. The cytolytic units of PDAK cells in this patient appeared to be substantially higher compared to those in PD patients. TCR gene usage analysis on PDAK cells revealed preferential usage of TCRVbeta segments. These results suggest that adoptive immunotherapy using PDAK cells for cancer patients with antigen-positive lung metastasis is safe and feasible, and tumor response should be examined in a future clinical trial

Adult↗