Biomedical subjects

K Minami

Publications and source records attributed to K Minami.

454 records · Page 26Linked to original sources

PubMedDate not supplied

T-cell receptor V beta gene usage of human cytotoxic T-cell clones obtained from gastric cancer patients.

Nine T-cell clones have been established from tumor-infiltrating lymphocytes (TIL) isolated from ascitic fluid of a gastric cancer patient. Five of them retained cytotoxicity against autologous tumor cells (AuTu), and were all CD4+. Each clone had different usage of T-cell receptor (TCR) V beta gene as assessed by Southern blot analysis. Using AuTu and two allogeneic gastric cancer cell lines as targets, we selected three clones with unique cytotoxic properties. Two of these clones (Clone 1 and 2) preferentially lysed AuTu, but showed no or marginal cytotoxicity against allogeneic gastric cancer cells, and one clone (Clone 7) showed appreciable cytotoxicity against AuTu and allogeneic gastric cancer cells. In the detailed analysis of TCRV beta gene usage, Clone 1, 2, and 7 expressed V beta 13.1/D beta 1/J beta 1.5/C beta 1, V beta 3/D beta 2/J beta 2.4/C beta 2, and V beta 9/D beta 1/J beta 1.4/C beta 1, respectively, and the primary structures of the three TCRVb genes did not share any common features, neither in the sizes of their complementarity determining region 3 (CDR3) nor in their amino acid compositions. Interestingly, PBL of the same patient expressed CDR3 identical to that of Clone 2 and 7, but not that of Clone 1. CDR3 identical to that of Clone 2 and 7 were also detected in TIL of other gastric cancer patients. These results show that some AuTu-specific CTL included in TIL are circulating in peripheral blood, and that the CDR3 identical to that of the CTL is expressed extensively in TIL among different gastric cancer patients. Screening of the expression of the CDR3 in other gastric cancer patients is recommended to develop an immuno-therapy of gastric cancer based on antigenic peptide.

Adenocarcinoma↗

PubMedDate not supplied

Immunological properties of tumor cells genetically modified to secrete interleukin-2.

The immunological properties of interleukin-2 (IL-2) gene-transduced tumor cells were investigated in mice. A murine ovarian cancer cell line, OVHM, was retrovirally transduced with the human IL-2 gene (OVHM/IL-2) and the neomycin resistance gene (OVHM/Neo). OVHM/IL-2 cells continuously secreted IL-2 detected by ELISA using an antibody specific for human IL-2, and by a bioassay using an IL-2-reactive cell line (CTLL-2). When OVHM cells were inoculated subcutaneously into syngeneic B6C3F1 mice, OVHM/IL-2 cells but not parental (OVHM/P) or OVHM/Neo cells were regressed even though their rate of in vitro growth was comparable. This was not observed in nude mice, indicating the involvement of T lymphocytes in the regression of OVHM/IL-2 cells. The survival of mice inoculated intraperitoneally with OVHM/IL-2 cells was prolonged compared with those inoculated with OVHM/P cells. In irradiation experiments, IL-2 secretion by irradiated OVHM/IL-2 cells was retained for at least 5 days, although in vitro growth and in vivo tumorigenicity of irradiated OVHM/IL-2 cells were completely diminished. When mice were challenged with viable OVHM/P cells, survival of mice previously immunized with irradiated OVHM/IL-2 cells was prolonged compared to those immunized with irradiated OVHM/P cells, indicating a vaccine property of irradiated OVHM/IL-2 cells. Moreover, survival of mice with established ascites was improved upon injection of irradiated OVHM/IL-2 cells, indicating a therapeutic potential of OVHM/IL-2 cells. Tumor cells genetically engineered to secrete IL-2 may therefore be promising candidates for tumor vaccines and may provide a new mode of cancer immunotherapy.

Animals↗

PubMedDate not supplied

Generation of cytotoxic effector lymphocytes by MLTC using tumor cells genetically modified to secrete interleukin-2.

The in vitro generation of effector lymphocytes cytotoxic to cancer cells, was investigated with a mixed lymphocyte-tumor culture (MLTC) system using genetically modified human cancer cells, followed by stimulation with the interleukin (IL)-2 plus immobilized anti-CD3 antibody (IL-2/CD3) system. A gastric cancer cell line, GC022588 (HLA-A2, 24, B35, 55, C1,3), was retrovirally transduced with the human interleukin (IL)-2 gene (GC/IL-2) or the neomycin-resistance gene (GC/Neo). The secretion of biologically active IL-2 was detectable in GC/IL-2 cells but not in GC/Neo or parental GC022588 cells. The cytotoxic activity against the parental GC022588 cells of peripheral blood mononuclear cells (PBMC) was greater among PBMC activated with MLTC using GC/IL-2 than among those activated with MLTC using GC/Neo or without MLTC. The IL-2/CD3 stimulation could efficiently expand the effector lymphocytes without any reduction of the cytotoxic activity generated. The cytotoxic activity generated by this system was reproducible in several HLA-A2- or A24-positive donors. The effector lymphocytes could kill the other adenocarcinoma cells expressing HLA-A2 or A24. The phenotypes of the effector lymphocytes generated with the system were 40% CD4+ and 70% CD8+. Both phenotypes may have been responsible for the cytotoxicity. The removal of adherent cells from PBMC before the MLTC did not affect the generation of cytotoxicity, whereas neutralization of tumor-derived IL-2 with a specific antibody during the MLTC significantly inhibited the generation of cytotoxicity. These results suggest that IL-2 gene-transduction augments the immunogenicity of the tumor cells that efficiently stimulate lymphocytes to be cytotoxic, and that the IL-2/CD3 system may be practical for the expansion of effector lymphocytes for use in adoptive immunotherapy for cancer. The mechanism by which IL-2 gene-modified tumor cells stimulate immune reactivity was discussed.

Adenocarcinoma↗

PubMedDate not supplied

Management of concomitant occlusive disease of coronary and carotid arteries using cardiopulmonary bypass for both procedures.

The incidence of neurological complications following operative treatment of concomitant occlusive disease of coronary and carotid arteries has been reported to be between 0.7 and 18 per cent by different preoperative screening methods and surgical strategy. From the opening of our institution in November 1984 until March 1988 5443 open-heart procedures were performed. In 116 patients of 3540 consecutive coronary artery bypass grafting (CABG) candidates simultaneous carotid endarterectomy (TEA) was carried out because of hemodynamically relevant stenosis of one or both carotid arteries; 50 patients were neurologically symptomatic with TIA's and amaurosis fugax preoperatively. Sixty of 66 patients with asymptomatic carotid artery stenosis had either a morphologically severe stenosis of the carotid artery or multifocal occlusive disease of the extracranial supraaortic arteries. Prior to carotid-TEA cardiopulmonary bypass was inserted with mild hypothermia maintaining a beating heart for pulsatile body perfusion. An intraluminal shunt was only used in patients with bilateral carotid stenosis. Intraoperative EEG-monitoring was carried out to detect cerebrovascular insufficiency. In 108/116 patients no neurological complications were observed, but 6/116 patients had transient minor neurological symptoms. Two of 116 patients sustained a severe neurological deficit with hemiplegia and one of them died on the 21st postoperative day. Based on these data we conclude that patients requiring carotid TEA and CABG should be operated upon simultaneously using cardiopulmonary bypass for both procedures.

Aged↗