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Biomedical subjects

M Onuma

Publications and source records attributed to M Onuma.

At least 199 records · Page 11Linked to original sources
PubMed1988

Elicitation of bovine antibody to BLV-gp51 by BLV-vaccination.

This study was carried out to demonstrate sequential changes of antibody response to gp51 of BLV in bovine hosts injected with BLV-vaccine. BLV vaccine was prepared from culture fluids from FLK-BLV cells by treatment with 0.1% formalin for 48 hrs at 4 degrees C followed by ultrafiltration and lyophilization. Sterile vaccine containing 300 mg protein/ml, 1 mg of which was reactive by ELISA with monoclonal anti-BLV-glycopeptide up to 1:256 dilution, was injected intradermally with Freund's adjuvant into two 1-month-old Holstein calves seronegative for BLV. The first and second booster injections were given without adjuvant 3 and 15 weeks, respectively, after the initial injection. Sera collected weekly from these animals were analyzed to monitor development of antibody to BLV-gp51 by Western blotting and immunoferritin electron microscopy, as well as by ELISA to whole BLV and to BLV-gp51 partially purified by column chromatography. Antibody to BLV-gp51 was detected in sera collected 2 weeks after the initial injection, increased 2 weeks after the first booster, maintained its level during the following 10 weeks, and increased again 2 weeks after the second booster injection. Infectious BLV was not detected by syncytium-formation assay of lymphocytes collected 15 weeks after the initial injection. This study demonstrated sequential changes of anti-BLV-gp51 antibody elicited in bovine hosts subsequent to injection of formalin-treated BLV. Further analysis of bovine antibody to BLV-gp51 may help develop improved BLV-vaccine.

Animals↗
PubMed1987

Effect of platelet-derived factor on expression of bovine leukemia virus genome.

Plasma of cattle infected with bovine leukemia virus (BLV) contains a factor, plasma blocking factor (PBF), that inhibits the expression of viral genome in cultured lymphocytes from BLV infected cattle. When platelet lysate was added to this culture, BLV antigen became detectable in the culture and there are some factors (PDF) in platelet lysate which have inhibitory activity against PBF. The PDF was present in platelet from BLV-free cattle as well as BLV-infected cattle at relatively high titer. The effect of platelet lysate against PBF on the expression of BLV genome seemed to be irreversible.

Animals↗
PubMed1987

Structure of a defective provirus of bovine leukemia virus.

Defective proviruses of bovine leukemia virus (BLV) in the genomes of infected cells were investigated by using Southern blotting hybridization analysis with various portions of a cloned BLV DNA as probes. When nine independent tumors of enzootic bovine leukosis with a single proviral copy per cell were examined, a single defective provirus of BLV was found in one tumor and also in a bovine B cell line derived from this tumor. Hybridization analysis of this defective provirus revealed that it underwent deletion between the pol and env genes and contained no major deletion in the other regions.

Animals↗
PubMed1987

Detection of cross-reactive antibody to BLV p24 in sera of human patients infected with HTLV.

For detection of antibody to bovine leukemia virus (BLV) major core protein of p24 and cross-reactive antibody in human patients infected with human T cell leukemia virus type I (HTLV-I), monoclonal antibody, D432 against BLV p24 was used by competitive binding enzyme-linked immunoadsorbed assay (ELISA). In sera from cattle with enzootic bovine leukosis (EBL) which were positive for BLV antibodies by immunodiffusion test, 109 out of 112 (97.3%) were positive for BLV p24 antibody by competitive binding ELISA. By using the same procedures, 21 samples from adult T cell leukemia (ATL) patients and healthy carriers with HTLV-I were tested for cross-reactive antibody to BLV p24. All 21 samples were positive for HTLV-I antibodies by immunofluorescence test and/or ELISA. By competitive binding ELISA using non-treated BLV antigens, none of these 21 samples inhibited the binding of the D432. When the BLV antigen was treated by several different denaturation procedures, several HTLV-I positive samples showed the inhibition of the D432 binding and the most effective treatment was by 2-mercaptoethanol (2-ME). Sixteen out of 21 samples showed the presence of cross-reactive antibody against 2-ME-treated BLV antigens. The cross-reactivity of human sample to BLV p24 antigen was further confirmed by Western blotting of the 2-ME-treated BLV antigens. None of the 28 samples from leukemia patients other than ATL which were negative for HTLV-I antibodies showed inhibition of the D432 by the competitive binding ELISA.

Antibodies, Viral↗
PubMed1987

Radiolocalization of bovine lymphosarcoma cells in athymic mice, using a monoclonal antibody against tumor-associated antigens.

Mouse monoclonal antibody c 143 was purified and F(ab')2 fragments were generated by pepsin digestion and then radiolabeled with 125I. The 125I-labeled c 143 F(ab')2 fragments were injected into athymic mice bearing bovine lymphoid tumor cells. The fragments became preferentially localized in tumor tissues, but not in normal tissues, as determined by differential counting of tissue radioactivity. The fragments became localized specifically in those tumors that were reactive with c 143 in vitro, but did not become localized in unrelated tumors. Localization of labeled F(ab')2 fragments of a monoclonal antibody of the same isotype directed against Taka virus (a variant of Newcastle disease virus) was not observed in athymic mice bearing bovine lymphoid tumor cells. Tumors were detectable by radioimmunoscintigraphy, using radiolabeled c 143 F(ab')2 fragments, without background subtraction, and by use of silver-grain scattering in light microscopic autoradiography.

Animals↗
PubMed1987

Use of viable-cell ELISA for detection of monoclonal antibodies recognizing tumor-associated antigens on bovine lymphosarcoma cells.

An ELISA, using viable bovine lymphosarcoma cells, was developed to detect tumor-associated antigens (TAA) expressed on lymphosarcoma cells from cows with enzootic bovine leukosis (EBL). Monoclonal antibodies (MAB) against TAA were used. Using viable-cell ELISA, MAB reacted with tumor cells from 9 cows with EBL, but not with peripheral blood lymphocytes from 10 clinically normal cows. Titers of MAB against tumor cells from 1 cow with EBL were 2,048 (direct immunofluorescence assay), 8,192 (flow cytometry), 2,048 (fixed-cell ELISA), and 16,384 (viable-cell ELISA). Viable-cell ELISA was the most sensitive method for detection of TAA. Reactivities of 7 MAB to tumor cells from cows with EBL were compared between viable-cell ELISA and a complement-dependent antibody cytotoxicity test. Of 5 MAB with no cytotoxic activity against tumor cells, 3 were reactive against tumor cells from the same cow, as determined by viable-cell ELISA, with titers ranging from 128 to 2,048.

Animals↗
PubMed1986

Establishment of B-cell lines from tumor of enzootic bovine leukosis.

Two lymphoid cell lines were established from enzootic bovine leukosis tumor cells. Suspension cell cultures of these cell lines have been maintained in vitro for over 2 yr. The cell grew as floating cells without attaching to the glass surface. These 2 cell lines have B-cell surface marker, tumor-associated antigen on the cell surface and bovine leukemia provirus in the genomes.

Animals↗