Biomedical subjects

Y Oshimi

Publications and source records attributed to Y Oshimi.

24 records · Page 2Linked to original sources

PubMed1988

Ti (WT31)-negative, CD3-positive, large granular lymphocyte leukemia with nonspecific cytotoxicity.

A case of WT31-, CD3+ large granular lymphocyte leukemia is reported. On surface marker analysis, the proliferating cells were found to be CD3+4-8-16+ and WT31-. By two-color immunofluorescence staining, CD3+4-8- cells were found to be WT31-, and a small population of WT31+ cells expressed either CD4 or CD8. WT31-, CD3+ cells were also identified in a bulk culture of lymphocytes expanded in vitro. Because WT31 monoclonal antibody (MoAb) reacts with the nonpolymorphic epitope of the disulfide-linked heterodimer of the T cell antigen receptor (Ti), the absence of the WT31-reactive Ti determinant may represent an expression of different CD3-associated polypeptides. The rearrangement of the Ti-beta and Ti-gamma genes but not the immunoglobulin gene was demonstrated, and the single pattern of rearrangement indicated the monoclonal origin of the lymphocytes. When the lymphocytes were assayed for their cytotoxicity against K562, MOLT-4, Daudi, and Raji tumor cell lines, a broad spectrum of cytotoxicity for these tumor cells was observed, and the lymphocytes also exhibited antibody- and lectin-dependent cellular cytotoxicity and lymphokine-activated killer activity. Treatment with anti-CD2 and anti-CD3 MoAbs inhibited their nonspecific cytotoxicity. The anti-CD3-mediated inhibition of nonspecific cytotoxicity suggested that an as yet unidentified Ti, present in association with the CD3 molecule on these lymphocytes, serves as a specific receptor for target tumor cell recognition.

Antibodies, Monoclonal↗

PubMed1986

Cytotoxicity of interleukin 2-activated lymphocytes for leukemia and lymphoma cells.

Studies were undertaken to determine whether leukemia and lymphoma cells would be lysed by autologous and allogeneic lymphokine-activated killer (LAK) cells. Peripheral blood mononuclear cells (PBMC) from patients and normal donors were cultured for five days, 2 weeks, and 4 weeks with medium containing 2,500 units of recombinant interleukin 2 (IL-2) per mL, and their cytotoxicity was assayed by a five-hour 51Cr-release test. Of primary tumors isolated from patients with acute nonlymphoblastic leukemia, acute lymphoblastic leukemia, and non-Hodgkin's lymphoma, tumors of 37 out of 40 patients tested were shown to be susceptible to normal donors' LAK, and tumors of 18 of 20 patients tested were shown to be susceptible to autologous LAK. LAK cultured for longer periods showed a tendency to have lower cytotoxicity. LAK had also low, but significant, levels of cytotoxicity for nonmalignant target cells. Because PBMC expanded in IL-2-containing medium consisted mainly of OKT3-positive pan T cells, OKT8-positive suppressor/cytotoxic cells, and Leu-11-positive natural killer (NK) cells, and treatment with OKT3 and Leu-11 monoclonal antibodies (mAb) reduced LAK activity for autologous and allogeneic tumor cells, both T and NK cells appeared to be effector cells for LAK activity. Mechanisms of target-cell recognition in the LAK system seem to be different from those in alloreactive cytotoxic T lymphocytes (CTL) based on the results that, while cytotoxicity of alloreactive CTL was inhibited by the treatment of effector cells with mAb, OKT3, and OKT8, and by the treatment of target cells with a mAb that reacts with HLA class I antigen, LAK activity was not inhibited by the above treatment. When chromosomes of IL-2-expanded PBMC in nine patients and two normal individuals were analyzed, PBMC from one patient showed chromosomes of clonal abnormalities, and PBMC from five donors showed those of nonclonal abnormalities.

Antibodies, Monoclonal↗

PubMed1985

Natural killer-mediated lysis of normal and malignant target cells, and its regulation by monocytes.

After depletion of monocytes, natural killer (NK) cells were partially purified from peripheral blood by Percoll density gradient sedimentation. The NK cells were then cultured for 1 d and assayed for their cytotoxicity against various types of normal and malignant target cells. All types of target cells tested were found to be susceptible to NK cells. The susceptible targets were autologous T and B lymphocytes, mitogen-induced T and B blasts, monocytes, large granular lymphocytes, autologous or allogeneic lymphoma and leukemia cells isolated from patients, and cultured cell lines, including those resistant to interferon-activated lymphocytes. Such a broad spectrum of cytotoxicity was demonstrated in 1 d of culture, and freshly prepared NK cells were not cytotoxic, or, if anything, were less cytotoxic. Monocytes and their supernatants, added throughout the course of culture, markedly inhibited the development of their cytotoxicity. These results may suggest that, although NK cells having ability to lyse autologous normal and malignant target cells are present in vivo, their lytic activity is regulated by coexisting monocytes.

B-Lymphocytes↗

PubMed1985

Lysis of lymphoma cells by autologous and allogeneic natural killer cells.

Studies were undertaken to determine whether natural killer (NK) cells would lyse autologous and allogeneic lymphoma cells. When large granular lymphocytes, which are known to mediate NK activity, were enriched from peripheral blood and used as effector cells, they lysed autologous lymphoma cells of all of eight patients tested, and those of healthy donors lysed lymphoma cells of all of ten patients tested. The addition of interferon to the culture medium enhanced their cytotoxicity in three of the eight patients in the autologous effector-tumor system and in four of the ten patients in the above allogeneic system. On the basis of the unlabeled target competition test and the decrease in cytotoxicity with anti-NK antibody treatment, NK cells appeared to be the main cytotoxic effector cells for autologous and allogeneic lymphoma cells.

Adolescent↗

PubMed1985

Lysis of lymphoma cells by cultured large granular lymphocytes.

Studies were undertaken to determine whether in vitro-propagated large granular lymphocytes (LGL), which are known to mediate natural killer (NK) activity, would lyse autologous and allogeneic lymphoma cells. LGL from ten patients and two healthy donors were propagated in vitro for two to four weeks with interleukin 2-containing medium, and their cytotoxicity was tested in a 5-h 51Cr-release assay. Cultured LGL from all the patients and healthy donors demonstrated strong cytotoxicity against K562 target cells, a standard target in NK assay, while cultured LGL from the patients lysed autologous lymphoma cells from three of the ten patients tested and those of the two healthy donors lysed lymphoma cells from four of the ten patients. These findings indicate that, when LGL propagated in vitro in large numbers show lytic activity against autologous lymphoma cells, these LGL may have potential application in clinical trials.

Cells, Cultured↗

PubMed1983

Lysis of leukemia and lymphoma cells by autologous and allogeneic interferon-activated blood mononuclear cells.

Studies were undertaken to determine whether leukemia and lymphoma cells would be lysed by autologous and allogeneic interferon (IFN) activated peripheral blood mononuclear cells (PBMC). PBMC from healthy donors and from patients were cultured with and without 500 U of highly purified human fibroblast IFN/ml for 24 hr, and then their cytotoxic activity was assayed by a 5-hr 51Cr-release test. Of primary tumor cells isolated from patients, the cells of 5 of 15 patients with acute nonlymphocytic leukemia (ANLL), 5 of 9 patients with acute lymphocytic leukemia (ALL), 2 of 3 patients with chronic phase chronic myelogenous leukemia (CML), 2 of 3 patients with blastic phase CML, 1 patient with hairy cell leukemia, and 6 patients with diffuse non-Hodgkin's lymphoma were sensitive to IFN-activated PBMC of healthy donors, whereas the cells of 3 of the ANLL patients, 2 of the ALL patients, and 3 of the lymphoma patients were sensitive to unstimulated PBMC. Of the ANLL cells tested, myeloblasts, promyelocytes, and monoblasts were sensitive to either unstimulated or IFN-activated PBMC. Compared with the ANLL cells, the lymphoma cells were statistically significantly sensitive to activated effector cells (p less than 0.025). On the basis of the unlabeled target competition test and the recovery of cytotoxic cells within the fractions enriched in natural killer (NK) cells, NK cells appeared to mediate the above unstimulated and IFN-boosted cytotoxicity. In experiments using autologous effector-target cells from 11 patients, the addition of 500 U of IFN/ml enhanced the lytic activity of PBMC against autologous lymphoma cells in 1 patient, and higher concentrations of IFN, i.e., 2500 or 3500 U/ml, enhanced their cytotoxic activity against autologous leukemia or lymphoma cells in 4 of 8 patients. These data indicate that IFN-activated allogeneic PBMC are able to lyse both myeloid and lymphoid tumor cells, whereas higher concentrations of IFN are required to enhance lytic activity against autologous tumor cells.

Cytotoxicity, Immunologic↗