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Biomedical subjects

M Onuma

Publications and source records attributed to M Onuma.

At least 217 records · Page 12Linked to original sources
PubMed1986

Glycosphingolipids of normal bovine and enzootic bovine leukosis lymph node cells.

We analyzed glycosphingolipids from normal lymph node cells of seven cattle and lymph node cells of eight cattle with enzootic bovine leukosis. The neutral glycosphingolipids and gangliosides were analyzed by thin-layer chromatography. Both normal and tumorous lymph node cells had GlcCer, LacCer, and GbOse3Cer as major neutral glycosphingolipids. In the ganglioside fraction, GM3 was the predominant component in both normal and tumorous lymph node cells, and another component, ganglioside Gx fraction, was also prominent in tumorous lymph node cells. The structure of this ganglioside Gx fraction was elucidated by thin-layer chromatography, sugar analysis, neuraminidase digestion, and permethylation studies. This ganglioside Gx fraction was found to be a mixture of four ganglioside species. The structures of individual gangliosides Gx (1 to 4) were characterized as follows. 1: GD3, NeuAc alpha 2-8NeuAc alpha 2-3Gal1-4Glc-Cer. 2: GD3, NeuAc alpha 2-8NeuGc alpha 2-3Gal1-4Glc-Cer. 3: GD3, NeuGc alpha 2-8NeuAc alpha 2-3Gal1-Glc-Cer. 4: GD3, NeuGc alpha 2-8NeuGc alpha 2-3Gal1-4Glc-Cer. These GD3 species may be formed as a result of the induced synthesis inassociation with malignant transformation.

Animals↗
PubMed1986

No involvement of bovine leukemia virus in sporadic bovine lymphosarcoma.

Using various portions of a molecularly cloned bovine leukemia virus (BLV) DNA as probes, the possible integration of a BLV genome or a BLV-related sequence into the chromosomal DNA of sporadic bovine leukosis (SBL) tumor cells was investigated by Southern blotting analysis. Under stringent as well as nonstringent conditions of hybridization, neither BLV nor BLV-related sequence specific to SBL DNAs was detected in any SBL tumor examined. These results provide conclusive evidence for lack of the relation of BLV or a BLV-related agent to SBL.

Animals↗
PubMed1986

Antitumor effect of adriamycin entrapped in liposomes conjugated with monoclonal antibody against tumor-associated antigen of bovine leukemia cells.

Monoclonal antibody against tumor-associated antigen (TAA) expressed on bovine leukemia cells was conjugated to liposomes containing adriamycin (ADM), and the specificity and therapeutic effects of the conjugates were examined in vitro and in vivo using a TAA-positive bovine leukemia cell line as the target tumor. In vitro studies with the TAA-positive cell line clearly indicated that the antibody-conjugated liposomes containing ADM exerted selective effects on TAA-positive cells in the inhibition assay of 3H-thymidine incorporation. Three injections of liposomes containing ADM (4 mg/kg) into tumor-bearing nude mice significantly inhibited the tumor growth and the therapeutic effect of the antibody-conjugated liposomes was far greater than that of normal mouse IgG-conjugated liposomes as assessed in terms of tumor size.

Animals↗
PubMed1985

Existence of cytotoxic activity against BLV-transformed cells in lymphocytes from normal cattle and sheep.

Peripheral blood lymphocytes (PBL) from normal cattle and sheep were tested for their cytotoxic activity against several target cells using a 20-hour 51Cr release assay. The following characteristics of the effector cells were observed; 1) PBL from animals showed cytotoxic activity against two sheep cell lines (FLK and SF-28) that were transformed with bovine leukemia virus. However, normal sheep and bovine cells and Molony leukemia virus-induced mouse lymphoma cell line (YAC-1) were not killed by these cells. 2) A time course study showed that the activity was first observed at 4 to 8 hours and reached a maximum at 20 to 30 hours after incubation. 3) Cytotoxic activity was observed in both adherent and nonadherent cell fractions when PBL were passed through a nylon-wool column. This indicated that the effector cells showed some degree of adherence. 4) Treatment of PBL with carrageenan did not change the cytotoxic activity against target cells, indicating that phagocytic capability is not perhaps necessary for cytotoxicity to take place. These results indicate that the effector cells participating in the cytotoxic reaction resembled natural killer cells or natural cytotoxic cells which are present in murine and human systems. However, analysis of the cell surface markers of the effector cells is yet to be done in future studies.

Animals↗
PubMed1985

Topographical analysis of tumor-associated antigens on bovine leukemia virus-induced bovine lymphosarcoma.

Tumor-associated antigens (TAAs) expressed on tumor cells from cattle with enzootic bovine leukosis were divided into three groups by using 13 monoclonal antibodies: common TAA; partially common TAA; and individually distinct TAA. TAA was extracted from tumor cells and purified by ion exchange chromatography on diethylaminoethyl-cellulose and isoelectric focusing. The common TAA, which was detected on all tumors tested, was eluted with 0.6 M KCl in ion exchange chromatography on diethylaminoethyl-cellulose, and the isoelectric point of the antigen was 6.8. The partially common TAA, which was detected on some (but not all) of the tumors tested, was eluted with 0.4 to 0.8 M KCl, and the isoelectric points of the antigen were 5.3, 5.8, and 6.4. The individually distinct TAA was present in the fractions eluted with 0.4 to 0.8 M KCl, and the isoelectric point of the antigen was 5.5. Results of competitive binding assay and Western blot analysis showed that the common TAA was a polypeptide with a molecular weight of 74,000; that it has at least two independent antigenic regions; that the partially common and individually distinct TAAs were a polypeptide with a molecular weight of 64,000; and that the antigenic determinants on the common TAA, partially common TAA, and individually distinct TAA existed independently from each other.

Animals↗
PubMed1985

Tumor-associated antigens on bovine leukemia virus-induced bovine lymphosarcoma identified by monoclonal antibodies.

Thirteen monoclonal antibodies directed against tumor cells from cattle from enzootic bovine leukosis (EBL) were obtained. They reacted with tumor cells but not with normal bovine cells or bovine leukemia virus antigens. According to the reactivities of these antibodies with 19 individual tumors, the 13 monoclonal antibodies can be divided into three groups. Antibodies of the first group reacted with all the EBLs tested; those of the second group reacted with several, but not all, of the EBLs tested; and those of the third group reacted only with homologous tumor cells. Therefore, tumor-associated antigen (TAA) on the EBL tumor may possess common TAA, partially common TAA, and individually distinct TAA. The TAAs were solubilized from the tumor cells by treatment with 0.2% sodium deoxycholate and partially purified by diethylaminoethyl-cellulose column chromatography. Eleven of the 13 monoclonal antibodies reacted with this soluble TAA. The monoclonal antibodies belonging to the first group inhibited in vitro the growth of the bovine lymphoid cell line derived from the EBL tumor.

Adsorption↗
PubMed1985

Methylation pattern of the bovine leukemia provirus genome in bovine leukemic cells.

All the known genes of the bovine leukemia proviral genome were found to be heavily methylated in both fresh and short-term-cultured leukemic cells, the latter of which expressed viral antigens. However, the pXBL region appeared to be mostly demethylated or at least hypomethylated in both cells, indicating that there is a non-uniform methylation pattern of the proviral genome.

Animals↗
PubMed1985

Usefulness of monoclonal antibodies for detection of enzootic bovine leukemia cells.

Monoclonal antibodies against tumor-associated antigens (TAAs) expressed in the leukemic cells of enzootic bovine leukosis (EBL) were examined for their possible usefulness in detecting EBL tumor cells. The antibodies immunohistochemically reacted with EBL tumor cells and had cytotoxic activity against the cells but not against normal adult bovine peripheral blood lymphocytes (PBL) even after activation with mitogens. The TAA-positive EBL tumor cells also had B cell surface markers. The TAA was also found in several samples of PBL taken from BLV-infected healthy cattle (8 positive out of 81 tested), as well as in PBL from 13 out of 14 cattle with lymphocytosis but no evidence of tumor. Thus, monoclonal antibodies directed against TAAs might be a useful tool not only for diagnosing EBL but also for screening of BLV-infected cattle with the potential to develop tumors in the future.

Animals↗
PubMed1984

Comparison of the entire genomes of bovine leukemia virus and human T-cell leukemia virus and characterization of their unidentified open reading frames.

We have compared the sequence of the entire genomes of bovine leukemia virus (BLV) and human T-cell leukemia virus type I (HTLV-I). Both the gag and pol genes show overall strong homologies indicating the close evolutionary relationship of the two retroviruses. However, a surface glycoprotein portion of the env gene shows no appreciable homology, which probably reflects a difference in their host ranges. The 3' end portion of the BLV genome (designated as pXBL) contains an unidentified long open reading frame that has a typical protein-coding property. The potential product of this open reading frame may be a glycoprotein of approximately 40 000 daltons. We note that its amino acid sequence shows low but appreciable homology, especially in its N-terminal quarter, to that of the HTLV-I counterpart (pX product), and we thus suggest that BLV pXBL and HTLV-I pX have diverged from a common ancestral gene. It is tentatively concluded that both the putative pXBL and pX products are respectively produced from a spliced mRNA.

Amino Acid Sequence↗
PubMed1984

Monoclonal antibodies against BLV-transformed sheep cells. Brief report.

Hybrid cell lines were prepared by the fusion of BALB/c myeloma, P3X63Ag 8.653 cells with the spleen cells of BALB/c mice that were immunized with SF-28 cells, sheep fibroblasts transformed with BLV in vitro. Five clones of hybrid progeny produced cytotoxic IgG1 antibodies against SF-28 cells. The tested monoclonal antibodies showed cytotoxic activity against 4 out of 6 BLV-transformed sheep fibroblasts as well as SF-28 cells but failed to react with other cells, including BLV-producing FLK cells, bovine lymphosarcomas and normal sheep cells. These monoclonal antibodies showed suppressive effect on colony formation of SF-28 cells in soft agar culture.

Animals↗
PubMed1984

Induction of lymphosarcoma in sheep inoculated with bovine leukaemia virus.

Five sheep were experimentally inoculated with BLV in order to study the humoral immune response in animals infected with bovine leukaemia virus (BLV). During experimental periods of 46 months, 2 sheep died with leukaemia and one sheep showed splenomegaly and proliferation of tumour cells. The other 2 sheep were clinically normal. All of the inoculated sheep developed antiviral antibodies 1 month after inoculation and BLV could be re-isolated in lymphocytes 2 to 3 months after inoculation. Antibody against glycoprotein antigen (gp51) of BLV appeared earlier than the antibody against protein antigen (p24) and antibody titres of the former were higher than those of the latter during the course of the experiment. The complement dependent antibody cytotoxicity test was performed for the detection of antibody against BLV-related cell membrane antigen with 2 different kinds of target cells; FLK cells which are foetal lamb kidney cells chronically infected with BLV and SF-28 cells which are sheep fibroblasts transformed with BLV in vitro. All 5 sheep developed cytotoxic antibodies against both types of cells. In sera from two leukaemic sheep, cytotoxic antibody titres against SF-28 cells gradually decreased 30 months after inoculation and finally became negative one to 3 months before they died of leukaemia. However, these leukaemic sheep persistently produced antibodies against gp51 and p24.

Animals↗
PubMed1984

Suppression of natural cytotoxic activity of lymphocytes from cattle and sheep during the progress of bovine leukosis.

Peripheral blood lymphocytes (PBL) from cattle and sheep exhibited natural cytotoxicity on a fetal lamb kidney (FLK) cell line that was persistently infected with bovine leukemia virus (BLV) by 20-h 51Cr release assay. This cytotoxic activity was tested using PBL from normal cattle and sheep or BLV-infected animals. Although cytotoxic activity was also found in PBL from normal animals and from BLV-infected, but clinically healthy animals, the activity in PBL from animals with persistent lymphocytosis or leukemic animals was markedly decreased. The cytotoxic activity of PBL from 3 sheep sequentially tested before and during the disease was found to decrease gradually with the progress of the disease, and finally no cytotoxic activity was found at the time of death due to leukemia. These results suggest that the natural cytotoxic activity in PBL may have a role in immunosurveillance for progress of the tumor.

Animals↗
PubMed1984

Protection by vaccination against bovine leukemia virus infection in sheep.

Four preparations were tested as potential vaccines to protect sheep against bovine leukemia virus (BLV) infection. Purified glycoprotein (gp) 51 and protein (p) 24 antigens from the virus and glutaraldehyde-fixed fetal lamb kidney (FLK) cells chronically infected with BLV or sheep fibroblasts transformed with BLV (SF-28 cells) were used to inoculate 12 sheep. Each vaccine was given 3 times 2 and 4 weeks apart to 3 sheep. Six sheep vaccinated with gp51 antigen or fixed FLK cells developed complement-fixing antibody against gp51; the titers ranged from 1:8 to 1:128 at the time of virus challenge exposure at postinoculation week 9. Although the 6 sheep inoculated with p24 antigen or fixed SF-28 cells developed antibody against the respective inoculum, none of these sheep had gp51 antibody at the time of challenge exposure. All 12 vaccinated and 2 control sheep were challenge exposed with BLV-infected lymphocytes, and cells from the sheep subsequently were tested for infection by syncytium assay. Sheep inoculated with gp51 antigen or FLK cells were protected, but sheep inoculated with p24 antigen or SF-28 cells became infected. The cytotoxic activity of lymphocytes from protected and nonprotected sheep was not different from that of normal sheep. Seemingly, purified gp51 antigen or fixed FLK cells were capable of preventing BLV infection in sheep. Humoral immune responses to gp51 appears to have an important role in protection against BLV infection, whereas cytotoxic activity of lymphocytes does not.

Animals↗