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Biomedical subjects

T Osato

Publications and source records attributed to T Osato.

At least 73 records · Page 4Linked to original sources
PubMed1986

A virion-like particle (VLP) released from an Epstein-Barr virus-producing cell sub-line of P3HR-1: identification of a specific cellular DNA contained within VLPs.

A virion-like particle (VLP) was isolated from the culture fluid of P3HR-I cells. VLPs were separable from the enveloped Epstein-Barr virus (EBV) through rate-velocity sedimentation by virtue of their greater density. VLPs comprised electron-dense nucleoid material and the surrounding round or oval envelope which ranged from 100 to 150 nm in diameter. The polypeptide constitution of VLPs was very similar to that of enveloped EBV by SDS-polyacrylamide gel electrophoresis. VLPs contained reasonably specific cellular DNA (VLP DNA) with a sedimentation coefficient of 48S, which was cleaved into 5, 8, and at least 30 specific DNA fragments by digestion with BamHI, SalI, and EcoRI, respectively. Blot hybridization data suggested a limited heterogeneous genomic organization of VLP DNA and the presence of a VLP DNA-related molecule(s) in human cord lymphocytes.

Cell Line↗
PubMed1986

Production of human monoclonal antibodies against Epstein-Barr virus-specific antigens by the virus-immortalized lymphoblastoid cell lines.

The possible production of human monoclonal antibodies against Epstein-Barr virus (EBV) was assessed through the EBV immortalization technique. When individual lymphocyte samples from 50 clinical patients and healthy donors were immortalized by EBV, 4 lymphoblastoid lines yielded antibodies to EBV antigens. These positive lines were cloned and each line yielded cultures that secreted monoclonal antibodies against either viral capsid antigen (VCA) or membrane antigen (MA) component. Above all, a clonal line TAKA-SP-8 produced 5 micrograms MA antibody/10(6) cells/ml for more than 12 months. The culture fluid specifically immunoprecipitated a single polypeptide with a size of 93K from both P3HR-1 and B95-8 cell extracts. FUKA-SP-3, on the other hand, secreted 5 micrograms VCA antibody/10(6) cells/ml for at least 8 months. This antibody recognized two polypeptides with sizes of 123K and 120K, from P3HR-1 and B95-8 cell extracts, respectively. When B95-8 and P3HR-1 EBV were treated with the human MA monoclonal, both nuclear antigen (EBNA) synthesis and early antigen (EA) induction were strongly inhibited. All EBV antibody-producing cultures were exclusively achieved from splenic lymphocytes of patients with autoimmune diseases, but not from other donors.

Antibodies, Monoclonal↗
PubMed1986

Epstein-Barr virus infection and oncogenesis in primary immunodeficiency.

Lymphomas occurred in 3 of 16 Japanese patients with ataxia telangiectasia (AT) and Wiskott-Aldrich syndrome (WAS). The patients had a persistently reactivated Epstein-Barr virus (EBV) infection with a remarkable decrease in virus-specific cellular immunity. In these patients, the B lymphocytes were more sensitive to EBV-induced events and to cellular proto-oncogene activation than seen in the healthy counterparts. This immunologic and genetic background was considered to explain the massive lymphoproliferation in these primary immunodeficiency disorders.

Adolescent↗
PubMed1986

Epstein-Barr virus-enhancing plant promoters in east Africa.

The extracts of a certain African plant species, Euphorbia tirucalli, were found to have markedly enhancing effects on the activation of latent Epstein-Barr virus (EBV) genomes in the EBV carrying lymphoblastoid cells and also on EBV-induced transformation of human lymphocytes. The Euphorbia tirucalli was especially noticeable in highly endemic areas of Burkitt's lymphoma (BL), an EBV-associated malignancy, in Kenya and Tanzania. The activation of the latent EBV genome and the EBV-induced transformation enhancement were also observed with the soil and drinking water taken around the plants, strongly indicating that the people living in BL endemic areas are frequently exposed to such an EBV-enhancing plant promoter substance.

Africa, Eastern↗
PubMed1985

Prevalence of a human retrovirus in native Japanese: evidence for a possible ancient origin.

The origin of a human retrovirus (ATLV or HTLV-I) is, at present, unknown although carriers of the virus have been found in Japan, the Caribbean basin and Africa. By means of a sero-epidemiological study, the Ainu people of Hokkaido, located in the northernmost island of Japan, were shown to have antibody to the virus in high frequency. Since the Ainu are regarded as descendants of the pre-agriculture native population of northern Japan, this finding appears to indicate that the retrovirus was already present in the aboriginal Japanese of prehistoric times.

Adolescent↗
PubMed1985

Immunoglobulin production in Epstein-Barr virus-transformed lymphoblastoid cell lines in patients with ataxia telangiectasia.

Peripheral blood lymphocytes from 7 patients with ataxia telangiectasia were transformed by Epstein-Barr virus, and lymphoblastoid cell lines (LCL) were established. Immunoglobulin levels in the supernatants of the LCL were measured in order to analyze immunological abnormalities, especially the low levels of serum IgA in these patients. We found that the geometric means of IgA production in the supernatants of the LCL from the 7 patients were significantly lower than those from 9 healthy controls (5.0 vs. 834 ng/ml, p less than 0.001). These results indicate that the low levels of serum IgA in ataxia telangiectasia are attributable at least in part to an intrinsic abnormality of B cells.

Adolescent↗
PubMed1985

[Epidemiological studies of adult T-cell leukemia virus in patients with adult T-cell leukemia (ATL) and ATL-related diseases in Hokkaido District of Japan].

Sera and peripheral blood lymphocytes in 40 clinical cases of adult T-cell leukemia (ATL) and 66 cases of mature T-cell malignancies in Hokkaido district, the most northern part of Japan, were examined for the infection with ATL virus (ATLV). All of the 40 ATL patients (100%) had antibodies to ATLV-associated antigen (ATLA) and 13 (19.7%) of the 66 patients with mature T-cell malignancies other than ATL were also positive for anti-ATLA. When the peripheral ATL lymphocytes were assessed after short time cultivation, both ATLA antigen and C type virus particles were detectable. In contrast to the high prevalence of ATLV antibodies in these patients, the positivity in 30,000 control individuals in this district was 0.73%. It was calculated that 8 patients of a 40,000 seropositive population are diagnosed annually as ATL in this particular northern part of Japan.

Adult↗
PubMed1985

[Prevalence of antibody to adult T-cell leukemia virus in Hokkaido District].

In order to investigate the spread of adult T-cell leukemia (ATL) virus in the inhabitants of ATL-non-endemic Hokkaido, we surveyed the antibodies to ATL-associated antigen (ATLA) in 29516 healthy individuals by indirect immunofluorescence test using MT-1 for target cell. Of the healthy inhabitants, only 219 individuals (0.74%) were anti-ATLA positive as carriers. Prevalence of anti-ATLA was 0.63% (111 of 17590) in males and 0.91% (108 of 11926) in females. This difference by sex is significant. In several regions, the inhabitants were found to show relatively high incidence (greater than 2%) of the antibodies, and these regions have a tendency to cluster around the western side of Hidaka mountains or Akan area. The highest rate (5.2%) of anti-ATLA positive carriers was shown in a certain town of Hidaka area.

Adolescent↗
PubMed1985

[High prevalence of adult T-cell leukemia virus infection in family members of adult T-cell leukemia patients in non-endemic Hokkaido District].

Family members of non-endemic Hokkaido patients with adult T-cell leukemia (ATL) were assessed for the prevalence of ATL virus (ATLV) infection. Immunofluorescence test showed that 53 (39.8%) of 133 healthy family members of 23 ATL patients were positive for antibodies of ATLV-associated antigen (ATLA). When seropositive T-cell malignancies other than ATL and healthy controls in Hokkaido were examined, 10 of 33 family members (30.3%) of 9 patients and 3 of 18 family members (16.7%) of 5 donors had ATLA antibodies, respectively. In sharp contrast, the overall seropositivity in this northern part of Japan was 0.73%. None were seropositive (0%), when 26 family members of 6 patients with acute myeloid leukemia sero-converted by blood transfusion during the course of the disease.

Adolescent↗
PubMed1985

Globoside and Forssman synthases in human lymphocytes exposed to Epstein-Barr virus and mitogens.

The activities of two glycolipid synthetases, globoside synthase or UDP-N-acetylgalactosamine-trihexosylceramide beta-N-acetylgalactosaminyltransferase (beta-GalNAc transferase; EC 2.4.1.79) and Forssman synthase or UDP-N-acetylgalactosamine-globoside-alpha-N-acetylgalactosaminyltransfer ase (alpha-GalNAc transferase; EC 2.4.1.88), were assayed in various human lymphoblastic cell lines. The activity of beta-GalNAc transferase was much higher than that of alpha-GalNAc transferase except in Molt 3 and Molt 4 lines, which were derived from T-cells. In cultivated human peripheral lymphocytes concanavalin A (Con A), lipopolysaccharide (LPS), and Epstein-Barr virus (EBV) stimulated the activities of alpha- and beta-GalNAc transferases in addition to having their known stimulative effect on thymidine incorporation. Characteristic differences between alpha- and beta-GalNAc transferases were noted in the responses to the above mitogens, but activities of both enzymes were greatly increased by exposure of the lymphocytes to EBV. Treatment of lymphocytes with either dactinomycin (actinomycin D) or cycloheximide 24 hours after the addition of Con A, LPS, or EBV decreased the activities of the transferases. This observation suggests that stimulation of alpha- and beta-GalNAc transferases requires transcriptional and translational processes.

Cell Line↗
PubMed1985

Establishment and characterization of Ph1-positive and Ph1-negative lymphoblastoid cell lines from a patient with chronic myelogenous leukemia.

Two continuously growing in vito cell lines, PB-1049 and LN-1049, were established from a patient with Ph1-positive chronic myelogenous leukemia in extramedullary blastic crisis. PB-1049 was established from Epstein-Barr virus (EBV)-infected peripheral lymphocytes of the patient and had a 46,XY,t(9;22) karyotype. This cell line was shown to be tumorigenic in nude mice, and cultured cells recovered from the tumor nodule showed a 46,XY,6p+,t(9;22) stem line karyotype. LN-1049 was derived from a lymph node culture of the same patient, and was found to be non-tumorigenic in nude mice and karyotypically normal. Immunological examinations on EBV-induced antigens, surface and cytoplasmic immunoglobulin, and monoclonal antibodies, and some enzymatic and electron microscopic studies revealed that both cell lines had attained differentiation into late-B cell stage.

Animals↗
PubMed1984

Interferon production by Epstein-Barr virus in human mononuclear leukocytes.

Interferon (IFN) production following exposure to Epstein-Barr virus (EBV) was studied in primary human mononuclear leukocytes. When the leukocytes were exposed to EBV (strain B95-8 or P3HR-1) the IFN level reached a maximum 24 h after exposure to the virus, and a gradual decrease followed. A linear relationship was obtained between the input dose of EBV and the IFN titre. The IFN inducibility of leukocytes did not correlate with the EBV infectibility. IFN was also induced by u.v.-inactivated EBV and heat-inactivated EBV, but not by neutralized virus. IFN inducibility varied among adult donors, but there was no significant difference between EBV-seropositive and -seronegative groups. The response of cord blood leukocytes, however, was lower than that of the cells from adults. The activity of all IFN samples in this study was stable to acid and heat and exclusively neutralized by anti-human IFN-alpha. B cells, T cells and NK cells all produced IFN in response to EBV, but monocytes did not.

Adult↗
PubMed1984

A case of Japanese Burkitt's lymphoma associated with EB virus.

A 6-year-old girl was admitted for cervical lymphadenopathy. She was diagnosed histologically as having Burkitt's lymphoma with partial involvement of follicles. Immunological study of a biopsy specimen demonstrated that many cells were surface immunoglobulin (lambda light chain)-positive, and chromosomal analysis revealed a translocation of (8;14) (q24;q32) in all blastic cells. Her serum antibody titers to Epstein-Barr virus (EBV) capsid antigen and to early antigen were 1:320 and 1:160, respectively, and most of the cells from the lymphoma biopsy specimen were EBV-associated nuclear antigen (EBNA)-positive. In addition, EBV DNA/DNA reassociation kinetic analysis showed 22 EBV genome equivalents per cell. Complete remission was obtained by CHOP therapy (consisting of cyclophosphamide, adriamycin, vincristine, and prednisolone) combined with cervical irradiation. She is in complete remission now (17 months after the onset).

Antigens, Viral↗
PubMed1983

Multiplicity-dependent induction of viral capsid antigen in Raji cells superinfected with Epstein-Barr virus.

A quantitative analysis of Epstein-Barr virus (EBV)-induced early antigen (EA) and viral capsid antigen (VCA) syntheses was carried out in Raji cells superinfected with purified, concentrated P3HR-1 EBV. When the cells were exposed to the virus and assessed by immunofluorescence and immunoprecipitation, EA induction occurred significantly (17%) but not VCA (less than 1%), at a low-input multiplicity of infection (MOI) of 10 EBV DNA copies/cell. In contrast, at a high MOI of 500 EBV DNA copies/cell, the majority of cells were positive for both EA (82%) and VCA (61%). The latter VCA synthesis was accompanied by the replication of EBV DNA. Kinetic studies showed that EA induction was directly proportional to the dilution of the infecting virus, while VCA was made following three-hit kinetics. The implications of these results are discussed in relation to the heterogeneous nature of P3HR-1 EBV and a possible role of EA in VCA synthesis.

Antigens, Viral↗