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Biomedical subjects

M Onuma

Publications and source records attributed to M Onuma.

At least 181 records · Page 10Linked to original sources
PubMed1990

Production and characterization of monoclonal antibodies against chicken lymphocyte surface antigens.

A panel of monoclonal antibodies (mAbs) with specificity for chicken lymphocyte surface antigens was established and characterized based on their reactivities against chicken lymphoid cells and tumor cell lines on flow cytometry. Three mAbs (7-3G-2, 7-2E-8, and JB-2) reacted preferentially with thymocytes, however, none of them reacted with Marek's disease derived T lymphoblastoid cell lines. Four mAbs (6-27A-1, 4-5C-5, Lc-4, and Lc-6) reacted with spleen cells and peripheral blood leukocytes as well as thymocytes. All seven mAbs reacted with chicken embryonic thymocytes from day 12 of embryonic life onward. All mAbs showed no reactivity against bursal lymphocytes.

Animals↗
PubMed1990

Characterization of two monoclonal antibodies which recognize different subpopulations of chicken T lymphocytes.

Distribution among peripheral T lymphocyte subpopulations and biochemical properties of the chicken lymphocyte surface antigens defined by monoclonal antibodies (mAbs) Lc-4 and Lc-6 were examined. Two-color immunofluorescence analysis revealed that Lc-4 and Lc-6 antigens were expressed on mutually exclusive subpopulations of peripheral T lymphocytes but not on B lymphocytes. Lc-4 mAb precipitated a polypeptide with apparent molecular mass of 35 and 65 kilodalton under reducing and non-reducing conditions, respectively. These results indicated that the antigen recognized with Lc-4 was closely similar in tissue distribution and biochemical property to mammalian CD8 antigen.

Animals↗
PubMed1989

Tumor-associated antigen on bovine leukemia virus-induced bovine lymphosarcoma.

Specific tumor-associated antigen (TAA) was detected on enzootic bovine leukosis (EBL) cells by monoclonal antibodies against TAA. One of the monoclonal antibodies, c143, reacted with all EBL tumor cells tested but not with bovine leukemia virus (BLV) antigens. c143 reacted slightly with bovine fetal thymus and mitogen-stimulated lymphocytes from BLV-free cows but not with normal bovine lymphoid cells. TAA may be a good tumor marker of EBL tumor cells. We sacrificed eight TAA-positive but clinically normal animals and examined them in order to elucidate whether or not they had gross or histological tumors. At necropsy, four animals had tumors macroscopically. Three animals had no tumors histologically but had initial lesions showing follicular hyperplasia and the TAA on affected lymph nodes. The one remaining showed medullary hyperplasia in the spleen but there were no findings of tumors. Thus, c143 is a useful tool not only for diagnosing EBL, but also for screening of BLV-infected cattle with potential to develop tumors in the future.

Animals↗
PubMed1989

Immunohistological demonstration of virus and tumor associated antigens in tissues experimental and spontaneous bovine leukemia virus (BLV) infection.

Expression of bovine leukemia virus (BLV) antigens in vivo has not been shown. After BLV infection, however, production of antibodies directed towards BLV proteins (e.g. gp51) can be easily demonstrated. Thus, production of BLV proteins has to take place somewhere in infected cattle. Tissues and organs of experimentally infected cattle were fixed in acetone and embedded in paraffin. Monoclonal antibodies directed to gp51 were used to demonstrate BLV expression immunohistologically by the peroxidase-antiperoxidase (PAP) method. The same samples were also used to demonstrate a tumor associated antigen (TAA) employing a monoclonal antibody. Our results indicate that very few cells, found in the intestinal mucosa, produce gp51 in vivo. The expression of TAA, however, increases significantly shortly after infection with BLV and remains high throughout life.

Animals↗
PubMed1989

Chemotherapy and immunotherapy of bovine leukosis.

To prevent the progression of the disease, we treated leukemic or preleukemic cows with (1) adriamycin (ADM) entrapped in liposomes conjugated with monoclonal antibody, c143, against tumor-associated antigens (TAA) of bovine leukemic cells and (2) an immunotherapy using an immunopotentiator consisting of the cell wall skeleton of Nocardia rubra (N-CWS). Five leukemic or preleukemic cows with TAA-positive peripheral blood lymphocytes (PBL) received four injections of ADM alone (0.4 mg/kg body weight) or c143-conjugated liposomes containing the same dose of ADM (L-ADM-c143) through the jugular vein at about 4-day intervals. In three animals treated with L-ADM-c143, the TAA-positive cells gradually decreased with treatment and finally two animals became TAA-negative during a 6-week period and a 14-week period after treatment, respectively. About 6 weeks later, however, TAA-positive cells gradually increased. In the control, two animals treated with ADM alone showed no decrease of TAA-positive cells. Five TAA-positive animals with enlarged subcutaneous lymphatic nodules, each nodule estimated to be from 1 to 4 cm3 in size, were treated by injection of N-CWS into the tumors. Complete regression of tumor was observed in seven out of ten tumors treated in five animals. Decrease of TAA-positive cells was also observed in PBL for all five treated animals. In one animal, the TAA-positive cells remained low for at least 280 days after treatment. This study documents that ADM treatment and intralesionally administered N-CWS are effective in the treatment of bovine leukosis.

Adjuvants, Immunologic↗
PubMed1989

Regression of bovine lymphosarcoma by treatment with cell-wall skeleton of Nocardia rubra.

Five bovine-leukaemia-virus-positive cattle with enlarged subcutaneous lymphatic nodules and having tumour-associated antigens (TAA) in their peripheral blood lymphocytes (PBL) were treated by injection of the cell-wall skeleton of Nocardia rubra (N-CWS) into the nodules. All treated animals received two or three injections of N-CWS (each 0.5-4 mg per nodule) at 2 or 4-week intervals. The effect of the treatment was evaluated by the size of the nodules. Complete regression of nodules was observed in seven out of ten nodules treated in five animals. Decrease of TAA-positive cells was also observed in their peripheral blood lymphocytes for all five treated animals. In one cow, the TAA-positive cells remained low for at least 280 days after treatment.

Adjuvants, Immunologic↗
PubMed1989

The effect of GD3 ganglioside obtained from bovine lymphosarcoma on bovine normal mononuclear cell.

The effect of immunological function of GD3 on normal bovine lymphocyte was examined with various in vitro assay systems. The GD3 level in sera from enzootic bovine leukemia (EBL) cattle was significantly increased compared with that of normal cattle (EBL: 0.62 +/- 0.24 microgram/ml; normal cattle: 0.33 +/- 0.09 microgram/ml, P less than 0.05). Lymphocyte blastogenesis elicited by concanavalin A was inhibited by addition of a 50 micrograms/ml concentration, or more, of GD3. Inhibitory effect of GD3 in IL-2-dependent T cell line and EBL tumor cell line was hardly observed compared with normal peripheral blood mononuclear cells. GD3 also inhibited mixed lymphocyte reaction and allo cytotoxic T lymphocyte reaction.

Animals↗
PubMed1989

Antitumor effect of adriamycin entrapped in liposomes conjugated with anti-bovine tumor antigen monoclonal antibody in leukemic cows.

Monoclonal antibody c143 against tumor-associated antigen (TAA) expressed on bovine leukemia cells was conjugated to liposomes containing adriamycin (ADM), and therapeutic effects of conjugates were examined in leukemic or preleukemic cows to prevent the progression of the disease. Five cows with TAA-positive in their peripheral blood lymphocytes were divided into two groups. Each group of cows received 4 injections of ADM alone (0.4 mg/kg) or c143-conjugated liposomes containing the same dose of ADM (L-AMD-c143) through the jugular vein at about 4 day intervals. In three animals treated with L-ADM-c143, the TAA-positive cells gradually decreased with treatment and finally two animals became TAA-negative during a 6 week period and a 14 week period after treatment, respectively. In the control, two animals treated with ADM alone showed only a slight decrease of TAA-positive cells.

Animals↗
PubMed1989

Bar-structure in bovine erythrocytes infected with Theileria sergenti.

The purpose of this study is to elucidate some morphological characteristics of the bar-structure in bovine erythrocytes infected with Theileria sergenti. The bar-structure, the veil or the both were observed in infected erythrocytes. Infected bovine erythrocytes were classified into four types according to the included structures. Infected cells containing bar-structures increased with the progress of parasitemia. In Giemsa-stained blood preparations, bar-structures appeared purplish-red and measured a mean of 1.6 micron in length and up to 0.1 micron in width. Bar-structures were usually straight, sometimes S-shaped, and located in the periphery of infected erythrocytes. In the direct fluorescent antibody test with T. sergenti-positive bovine serum both piroplasms and bar-structures exhibited fluorescence. However, in the indirect fluorescent antibody test with monoclonal antibodies against piroplasms only piroplasms showed a highly specific fluorescence. Electron microscopy revealed that bar-structures were vesicular in structure, surrounded by a double membrane connected to the host cell membrane.

Animals↗
PubMed1989

Escherichia coli associated endotoxemia in dogs with parvovirus infection.

Escherichia coli bacteremia and endotoxemia were observed in 3 adult mongrel dogs which had been prediagnosed as canine parvoviral disease. The endotoxin level was 46.5 pg/ml in the plasma of clinical cases, while 2.3 pg/ml in healthy controls. The microflora of the feces was confused in the clinical cases. The percentage of E. coli was major in the feces. Serologically similar strains were isolated from the blood. These strains did not produce enterotoxins such as heat-stable enterotoxin (ST) and heat-labile enterotoxin (LT). Histopathologically, the lesions in the small intestine consisted of epithelial degeneration and necrosis. Viral inclusion bodies were frequently observed in the epithelial cells. Disseminated intravascular coagulation was observed in various tissues including the liver and small intestinal submucosa. After experimental infection with CPV, all dogs showed various clinical signs. CPV was positive in the feces. Endotoxin level in the plasma gradually increased and high level continued for long period from 10 to 30 days. Mean maximum level of endotoxin in the experimental dogs was 73.6 pg/ml. These results indicate that intestinal flora plays a important role in the pathogenesis of CPV infection and that endotoxin is one of the factors which predispose to severe disease after the infection.

Animals↗
PubMed1989

Further phenotypic characterization of target cells for bovine leukemia virus experimental infection in sheep.

To determine the phenotype of target cells for bovine leukemia virus (BLV) infection in sheep, we analyzed blood lymphocytes from BLV-infected clinically healthy and leukemic sheep by use of monoclonal antibodies. In clinically healthy and leukemic sheep that were BLV-infected, the blood concentration of T lymphocytes was within normal values, but the number of B lymphocytes was increased in several cases. In addition, the number of blood lymphocytes expressing the BLV antigen correlated well with that of B lymphocytes. Double immunofluorescence staining demonstrated that lymphocytes expressing BLV antigens bore B-cell but not T-cell surface markers. Moreover, neoplastic cells in the lymph nodes of leukemic sheep were stained immunohistochemically with an anti-B monoclonal antibody but not with any of anti-T monoclonal antibody tested, indicating that tumor cells are of B-lymphocyte origin. Collectively, these results show that BLV antigen-positive cells obtained from BLV-infected sheep that have no clinical signs and BLV-induced lymphosarcoma cells belong to the B-lymphocyte lineage.

Animals↗
PubMed1988

The screening of cattle with potential for developing leukemia by using monoclonal antibody against bovine leukemia cells.

Tumor cells from cattle with enzootic bovine lymphosarcoma (EBL) have a tumor-associated antigen (TAA) which is distinct from bovine leukemia virus (BLV)-induced antigens. We were able to sacrifice 8 TAA-positive cattle with no clinical signs of EBL and to examine whether or not they had gross or histological tumors. At necropsy, 4 animals had tumors macroscopically. Three animals had no tumors histologically but had initial lesions showing follicular hyperplasia and had the TAA on affected lymph nodes. The remaining one showed medullary hyperplasia in the spleen but there were no findings of tumors. These results suggest that most BLV-infected cattle which are TAA-positive but have no clinical signs of EBL, do have tumors and have a higher potential for developing EBL in the future when compared to BLV-infected but TAA-negative cattle.

Animals↗
PubMed1988

Occurrence of respiratory syncytial virus subgroup A and B strains in Japan, 1980 to 1987.

The subgroup characteristics of 71 strains of respiratory syncytial virus (RSV) isolated in Sapporo, Japan, during 5 epidemic years from 1980 to 1987 were determined by the use of 17 monoclonal antibodies (MAbs) raised against the RSV Long strain, which is now recognized as the prototype subgroup A strain. Nine of these MAbs immunoprecipitated the fusion protein (F), five immunoprecipitated the large glycoprotein (G), two immunoprecipitated the nucleoprotein (NP), and one immunoprecipitated the phosphoprotein (P). Based on the pattern of reaction of these MAbs to RSV isolates in an indirect immunofluorescence assay, we were able to distinguish two different subgroups. Subgroup A strains reacted to all 17 MAbs. Subgroup B strains reacted to none of the anti-G MAbs, eight of the nine anti-F MAbs, and all anti-NP and anti-P MAbs. Subgroup A included 38 (53.5%) isolates from every epidemic year. Subgroup B included 32 (45.1%) strains isolated in the last 4 epidemic years. One virus strain with an intermediate character of reactivity was isolated in 1983. From the first epidemic year, six subgroup A strains and no B strains were isolated. During the next three annual epidemics, subgroup B strains were predominantly isolated, i.e., 8 of 13, 10 of 13, and 13 of 17 strains. However, in the last epidemic year only one strain of 22 isolates belonged to subgroup B, and the remainder belonged to subgroup A. This variability of dominance in the occurrence of different RSV subgroup strains may suggest a possible role of the subgroup-specific immune response in RSV epidemics.

Antibodies, Monoclonal↗