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Biomedical subjects

K Sugamura

Publications and source records attributed to K Sugamura.

At least 217 records · Page 12Linked to original sources
PubMed1985

trans-Activation of the human T-cell leukemia virus long terminal repeat correlates with expression of the x-lor protein.

Cell lines established directly from adult T-cell leukemia-lymphoma patients or immortalized by human T-cell leukemia virus type I (HTLV-I) in vitro that do not produce complete HTLV virions were characterized both for the content of viral proteins and for the presence of trans-acting factors activating gene expression under the control of the HTLV long terminal repeat. The expression of the 42-kilodalton HTLV x-lor product correlated with trans-activation of the long terminal repeat. The implications of this study for understanding the role of the HTLV x-lor product in the initiation and maintenance of T-lymphocyte transformation are discussed.

Deltaretrovirus↗
PubMed1985

Immortalization of BGDF (BCGF II)- and BCDF-producing T cells by human T cell leukemia virus (HTLV) and characterization of human BGDF (BCGF II).

Human peripheral T cells were transformed by human T cell leukemia virus (HTLV), and T cell lines producing BGDF (BCGF II) and BCDF were established. Among these cell lines, a cell line, TCL-Na1, secreted the highest level of both BGDF and BCDF, and the amount of BCDF secreted by TCL-Na1 cells was 900-fold more than that produced by PHA-stimulated T cells. Within the limits of our examination, none of the HTLV-transformed T cell lines produced IL 2 or BSF-p1 (BCGF I). BCDF produced by TCL-Na1 cells had a m.w. of 35,000 and a pI value of 5.5, being separated from BGDF, which was eluted in the fractions corresponding to m.w. of more than 60,000 and pI values of 5 to 6. BGDF induced both proliferation and IgM secretion in a mouse leukemic B cell line, BCL1, and these activities were not separated by either isoelectric focusing or gel filtration in the presence or absence of 0.1% Triton X-100, suggesting that the molecule designated BGDF exerted both growth and differentiation activities. BGDF acted on normal mouse B cells to induce proliferation as well as IgM secretion. The target cells of BGDF were in vivo activated B blast cells. BGDF acted on DXS-activated murine B cells to induce both proliferation and IgM secretion but not anti-Ig-activated B cells, indicating that BGDF and BSF-p1 were different molecules.

Animals↗
PubMed1984

Microplate method for retrovirus-induced transformation of normal human T-cells.

An adult T-cell leukemia virus (ATLV) producer cell line (TL-Su) derived from a healthy ATLV-carrier, was used for virus-induced transformation of normal human T-cells. The transformation was carried out on microplates by co-cultivation of a limiting number of normal peripheral blood leukocytes (PBL) as transformed target cells and 2 X 10(4)/well of TL-Su cells irradiated lethally. The frequency of establishment of transformed cell lines correlated with the dose of PBL. The transforming target cell number was estimated to be approximately one per 500 PBL by the microplate method using TL-Su effector cells. When 1 X 10(3) PBL per well were plated, more than 90% of wells showed immortalizing transformation of PBL. Twenty transformed cell lines obtained from microplates with 500 PBL per well were shown to be of T-cell lineage. Ten of them were defined as belonging to the helper/inducer T-cell subset with Leu 3a antigen, and 4 were demonstrated to be of the cytotoxic/suppressor T-cell subset with Leu 2a antigen. The transformed cells always expressed Tac and OKT9 antigens (considered to be IL2 and transferrin receptors respectively). ATLV antigens were also expressed in all these cell lines tested, but their molecular species detected by radioimmunoprecipitation varied regardless of PBL donors and T-cell subsets. We propose this microplate transformation method as an advantageous system for obtaining abundant T-cell lines and for screening their immunological functions.

Antigens, Surface↗
PubMed1984

Cell surface phenotypes and expression of viral antigens of various human cell lines carrying human T-cell leukemia virus.

Human T-cell leukemia/lymphoma virus (HTLV)-carrying cells from various origins were characterized by cell surface markers and expression of HTLV antigens. Eight cell lines named TCL were obtained by transformation of peripheral blood leukocytes (PBL) of healthy donors or HTLV carriers in cocultures with HTLV-producer MT-2 cells. Nine cell lines named ILT were interleukin 2 (IL2)-dependent cell lines cloned from PBL of ATL patients and healthy HTLV-carriers. Tc-Kan9 cell line was also an IL2-dependent cell line clonally established from PBL culture stimulated with autologous TCL cells. Five cell lines named TL were established in vitro directly from PBL of an adult T-cell leukemia (ATL) patient and from ILT cells of an ATL patient and three HTLV-carriers, respectively, to grow autonomously without IL2. All the TCLs, ILTs, TLs and Tc-Kan9 possessed Leu-I antigen, a pan-T-cell marker. Leu3a antigen, a helper/inducer T-cell marker, was expressed on five of eight TCLs and all of the ILTs and TLs. Leu-2a, a cytotoxic/suppressor T-cell marker, was detected only on Tc-Kan9 but not others. Fresh ATL leukemic cells of patients had a helper/inducer T-cell marker. Ia, OKT9 and Tac antigens, markers for activated and differentiated T cells, were strongly expressed on all of the cell lines tested and fresh ATL leukemic cells were weakly positive for these antigens. Expression of HTLV antigens detected by mouse monoclonal antibodies and an ATL-patient serum varied among these cell lines. One TL, two ILTs and most of the fresh ATL leukemic cells did not express HTLV antigens on the cell surface. The other cell lines were all positive for the surface viral antigens. However, molecular species of antigens defined by radioimmunoprecipitation with an ATL-patient serum were not always identical among the cell lines. Molecular weights of polypeptides detectable in most of the cell lines were 62K, 46K, 40K, 24K, 21K and 19K which could never be detected in several control T-cell lines. 68K and 28K polypeptides were frequently detected in MT-2 and TGLs. GIN14, a mouse monoclonal antibody against HTLV core protein (p19) detected not only p19 in various cell lines but also p28, p29, p31 or p40 in certain cell lines tested. B-cell lines named LCL were established and cloned from PBL of two HTLV-carriers by EB-virus-induced transformation and they also expressed HTLV antigens, Ia, OKT9 and Tac antigens.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1984

Retrovirus-induced expression of interleukin 2 receptors on cells of human B-cell lineage.

We provide direct evidence for interleukin 2 receptor (IL2R) induction by human T-cell leukemia/lymphoma virus (HTLV) in human B-cell lines. A lymphoblastoid B-cell line (LCL-Ter) was established by Epstein-Barr virus-induced transformation of peripheral blood lymphocytes derived from a healthy HTLV carrier and cloned in vitro. HTLV gp21 and/or p19 antigens were detected in eight LCL-Ter clones, all of which also expressed the IL2R antigens Tac and Hiei (defined by monoclonal antibodies). However, five other LCL-Ter clones, which were negative for the HTLV antigens, did not express the IL2R antigens. Furthermore, when the IL2R-negative B-cell line LCL-Kan, derived form a normal donor, was cocultured with HTLV-producer cells, three HTLV-carrying clones were obtained and found to constitutively express IL2R. IL2R induced by HTLV on these B-cell lines bound recombinant interleukin 2 and were similar in apparent molecular mass (approximately equal to 60 kDa) to the IL2R of peripheral blood lymphocytes stimulated with phytohemagglutinin.

Antigens, Surface↗
PubMed1984

Constitutive production of phagocytosis inducing factor(s) in a monocyte/macrophage lineage cell line (THP-1) by retrovirus-transformed human T cell lines.

Four human T cell lines, MT-2, TCL-Kan, TCL-As 2, and TCL-Haz, established from normal leukocytes by cocultivation with adult T-cell leukemia (ATL) virus (ATLV)-producing cells, produced constitutively phagocytosis inducing factor(s) (PIF) that induced phagocytosis in a human monocytic cell line, THP-1. These cell lines expressed ATLV-associated antigens (ATLA) as well as numerous virus particles, whereas the other twelve leukocyte cell lines tested, including T cell lines, B cell lines, and non-T and non-B cell lines, did not produce detectable amounts of the factor(s) in the culture supernatants. PIF was produced in the absence of serum and was not related to either ATLV-particles or viral structural proteins. Its activity was stable at 56 C for 30 min, but labile at 80 C for 30 min and at pH 2 for 20 hr. MT-2 and TCL-Kan produced large amounts of the factor(s) in the culture supernatants but little interferon-gamma (IFN-gamma) or colony stimulating factor (CSF) activity was detected; furthermore, the activity was not neutralized by rabbit anti-IFN-gamma sera. These observations suggest that some ATLV-transformed T cell lines produce PIF that is different from IFN-gamma and CSF.

Cell Line↗
PubMed1984

Constitutive production and characterization of interferon-gamma in a human T-lymphoblastoid cell line transformed by a human retrovirus.

A human T-lymphoblastoid cell line, TCL-Fuj, constitutively produced a large amount of human gamma interferon (IFN) in culture fluids and has sustained stable IFN production for more than two years. When cells were incubated in RPMI-1640 medium with 10% fetal calf serum for three days, IFN activity was detectable at a cell density of 6 X 10(4) cells/ml, whereas 2,000-16,000 units of IFN per ml were produced at 5-10 X 10(5) cells/ml. IFN production was also detected even in serumfree medium and as early as 2 hr after cultivation in fresh medium. IFN was inhibited by treatment of cells with either actinomycin D or cycloheximide, indicating the requirement of IFN-mRNA and protein for de novo synthesis. The molecular weight of the IFN was 45,000-60,000 as determined by Sephacryl S200 gel filtration. Two activity peaks corresponding to molecular weights of 22,000 and 39,000 were obtained by SDS-polyacrylamide gel electrophoresis. Analysis by isoelectric focusing revealed charge heterogeneity with four species at pIs of 6.0, 7.1, 8.6, and 9.3. Conventional IFN-gamma inducers, concanavalin A and 12-O-tetradecanoyl-phorbol-13-acetate, further enhanced the production of IFN in this cell line.

Cell Line↗
PubMed1984

A monoclonal antibody that defines p24, a core protein of adult T-cell leukemia virus, and its precursor.

A mouse hybridoma cell line, H15, produced monoclonal antibody reacting with all the adult T-cell leukemia (ATL) virus (ATLV)-bearing cell lines but none of the ATLV-negative cell lines tested. Binding of H15 antibody to ATLV-bearing cell surfaces was specifically blocked by anti-ATLV positive human sera. Radioimmunoprecipitation analyses revealed that the antigen detected by H15 antibody was p24, a core protein of ATLV. Pulse-chase experiments using H15 antibody led to the identification of a protein, p53, which could be a precursor of p24.

Antibodies, Monoclonal↗
PubMed1984

Human retrovirus-induced IL-2 receptors and their possible role in transduction of continuous cell growth signal.

The first half of this report describes direct evidence for the interleukin 2 receptor (IL-2R)-inducing ability of human T-cell leukemia/lymphoma virus (HTLV). When an Epstein-Barr virus (EBV)-transformed human B-cell line, LCL-Kan was infected with HTLV or transfected with plasmid DNA containing defective HTLV genome (long terminal repeat (LTR)-gag-pX-LTR), LCL-Kan cells were altered to express IL-2R which was indistinguishable from that of normal activated T cells. The second half of this paper reports that IL-2 could inhibit proliferation of HTLV-carrying T-cell lines which were spontaneously immortalized from IL-2-dependent cells or peripheral blood cells containing ATL leukemia cells. These results suggest that expression of IL-2R may be induced by HTLV in HTLV-transformed cells, where the IL-2R plays an important role in transduction of continuous cell growth signal.

Cell Division↗
PubMed1984

Specific cytolysis of fresh tumor cells by an autologous killer T cell line derived from an adult T cell leukemia/lymphoma patient.

Cytotoxic T cells (Tc) derived from one patient with adult T cell leukemia/lymphoma (ATL) killed fresh autologous lymphoma cells in vitro. The Tc were induced from peripheral blood leukocytes (PBL) of this patient during remission by multiple in vitro stimulations with an autologous ATLV-bearing cell line (ILT) that was previously established by cloning of PBL in the presence of interleukin 2 (IL 2). PBL from eight other ATL patients were stimulated in the same manner, and responder cells from a patient in remission also showed cytotoxicity specific for ATL virus (ATLV)-bearing cells. Fresh lymphoma cells were obtained in relapse and were used as target cells for the autologous Tc induced. They became susceptible to the Tc within 4 hr of in vitro incubation, and their susceptibility increased with incubation time for at least 12 hr. ATLV antigens on the cell surface of these lymphoma cells, however, were not detected by radioimmunoassay during these incubation periods, but were detectable after 16 hr of incubation. In addition, cytotoxicity against lymphoma cells was completely inhibited by autologous ILT cells used as "cold" target competitor cells. These findings indicate that the target antigen of the Tc was expressed on both autologous ILT cells and lymphoma cells, and it may be different from ATLV antigens detected by serologic methods. In addition, the data suggested allogeneic restriction of the Tc in that the preferentially killed allogeneic ATLV-bearing cells share several HLA antigens.

Adult↗
PubMed1984

Identification of a glycoprotein, gp21, of adult T cell leukemia virus by monoclonal antibody.

A mouse hybridoma cell line producing monoclonal antibody, F10, was established from mice hyperimmunized with cells bearing adult T cell leukemia (ATL) virus (ATLV). F10 antibody reacted with an ATLV structural polypeptide ( gp21 ) with a m.w. of 21,000 that was glycosylated on cell surfaces. The gp21 was expressed on cell surfaces of all ATL-associated antigen (ATLA)-positive human cell lines but not on ATLA-negative cell lines nor peripheral blood leukocytes stimulated with mitogens. The gp21 was also detected with anti-ATLA-positive human serum, and the binding of F10 antibody to ATLA-positive cell surfaces was significantly blocked by pretreatment with anti-ATLA-positive human sera. Double immunofluorescence staining with F10 antibody and anti-ATLA-positive human serum caused co-capping on cell surfaces, which suggests that gp21 co-exists with other ATLV antigens expressed on cell surfaces. Immunoprecipitation studies also suggested that the gp21 is a minor component of the ATLV envelope.

Animals↗
PubMed1983

Establishment of human cytotoxic T cell lines specific for human adult T cell leukemia virus-bearing cells.

Human cytotoxic T cells (Tc) specific for autologous adult T cell leukemia virus- (ATLV) bearing cells were induced in vitro. Peripheral blood leukocytes (PBL) from healthy donors were stimulated repeatedly with autologous ATLV-bearing T cells. In two out of four seropositive donors and one out of two seronegative donors, the responder cells showed cytotoxicity for autologous ATLV-bearing cells, but not for autologous PBL, autologous cloned T cell lines, Epstein Barr virus-transformed autologous lymphoblastoid B cell line (LCL) cells, or various ATLV-negative cell line cells. The effector cells induced were cytotoxic T cells possessing Leu-1 and Leu-2a antigens that were able to proliferate continuously in vitro with periodic restimulation by appropriate cells and supplementation with partially purified T cell growth factor (TCGF). Of three Tc lines tested, one exhibited significant cytotoxicity against allogeneic ATLV-bearing cells that shared HLA-A2 antigen with the effector cells, possibly indicating HLA-restriction of ATLV-specific Tc. HLA-restriction was also suggested by cold target inhibition of cytotoxicity. Interestingly, Tc from this individual could also kill fresh adult T cell leukemia cells that were not expressing the ATLV surface antigens. These results, together with the target specificities of other Tc lines, suggest the possibility of at least two distinct target antigens recognized by ATLV-specific Tc, with one of these antigens differing from the ones detected by serologic methods.

Adult↗
PubMed1982

Healthy carriers of a human retrovirus, adult T-cell leukemia virus (ATLV): demonstration by clonal culture of ATLV-carrying T cells from peripheral blood.

Adult T-cell leukemia virus (ATLV) or ATLV-associated antigen (ATLA)-positive cell clones were isolated from peripheral blood lymphocytes of all five anti-ATLA-seropositive healthy adults tested by a limiting-dilution culture method in the presence of T-cell growth factor (TCGF) but from none of six seronegative adults similarly tested. Although ATLA-positive cells were not always detected in mass cultures of the seropositive lymphocytes, they were found consistently in T-cell cloned cultures of those lymphocytes. Continuous cultures of the ATLA-positive clones obtained were dependent on TCGF. Five clones derived from each of the five donors were maintained for greater than 4 months and, during culture, all of them acquired the ability to grow without added TCGF. The ATLA-positive clones formed rosettes with erythrocytes and expressed Leu 1, Leu 3a, and Leu 4 antigens but not Leu 2a antigen. These results indicate that anti-ATLA-seropositive healthy individuals carry ATLV in T cells circulating in their peripheral blood.

Adult↗
PubMed1982

Expression of target antigen for Epstein-Barr virus-specific cytotoxic T cells on BJAB cells freshly infected with EBV.

The target antigen for Epstein-Barr virus (EBV)-specific cytotoxic T cells (Tc) was expressed on BJAB cells exposed to the B95-8 strain of EBV for at least one hour. Ultraviolet-light (UV)-irradiated noninfectious B95-8 virus also induced the target antigen on BJAB cells. Cold target competition tests suggested that the target antigen expressed on EBV-infected BJAB cells was distinct from the lymphocyte-detected membrane antigen (LYDMA) which was also recognized by the EBV-specific Tc and expressed on autologous EBV-Transformed lymphoblastoid cell line (LCL) cells. Neither of these target antigens for EBV- specific Tc was detected on the surface of EBV-genome positive BJAB cells which had been kept in a long term culture after EBV-infection. Thus, the virion antigen, especially the EBV-membrane antigen (MA), is a possible candidate for the target antigen expressed on EBV-infected BJAB cells. Lysis of EBV-infected BJAB cells was inhibited by target cell treatment with anti-beta 2 microglobulin (anti-beta 2M) antibody and induction of the effector Tc was dependent on the donor individual. These results suggested the possibility that the Tc recognizing EBV-infected BJAB cells are restricted by the major histocompatibility complex (MHC).

Animals↗
PubMed1982

Two distinct human cloned T cell lines that exhibit natural killer-like and anti-human effector activities.

Cloned T cell lines from mixed lymphocyte cultures stimulated with autologous Epstein Barr virus- (EBV) transformed lymphoblastoid cell line (LCL) cells were established using a limiting dilution technique in the presence of T cell growth factor (TCGF). The T cell lines included two distinct clones of cytotoxic T cells (Tc) in addition to EBV-specific Tc. A cytotoxic profile of one cloned line was similar to that of endogenous NK cells in peripheral blood. The other cloned Tc line showed an anti-human cytotoxicity. The susceptible targets for this latter Tc line were various human cells, including autologous LCL and peripheral blood lymphocytes (PBL), stimulated with pokeweed mitogen, along with NK-sensitive and NK-resistant cell lines. Weak cytotoxic activity was detected against various xenogeneic cell lines. Furthermore, autologous and allogeneic cloned T cell lines were resistant to killing by the anti-human effector clone. These t wo distinct cloned Tc lines expressed the Leu-1 and Leu-2a antigens, which are markers of suppressor/cytotoxic T cells.

Animals↗
PubMed1982

Heterogeneity of allogeneic restriction of human cytotoxic T cell clones specific for Epstein Barr virus.

Clones of human cytotoxic T cells (Tc) specific for Epstein Barr virus (EBV) were isolated from peripheral blood lymphocyte (PBL) cultures stimulated repeatedly with autologous EBV-transformed lymphoblastoid cell line (LCL) cells in vitro. The method employed to clone EBV-specific Tc was a limiting dilution technique utilizing T cell growth factor (TCGF). The EBV specificity of Tc clones was determined by showing that they were significantly cytotoxic for autologous LCL cells but not for either autologous PBL or (natural killer-sensitive) K-562 cells. Eight EBV-specific Tc clones derived from a single donor exhibited distinct cytotoxic patterns against allogeneic LCL targets. Two clones were cytotoxic to LCL targets sharing both HLA-A26 and B15 antigens with effectors, and killing by two other clones was strongly restricted to autologous LCL cells. The four remaining clones showed cytotoxicities against various allogeneic LCL targets irrespective of HLA antigen expression. Eight EBV-specific Tc clones derived from a second donor also exhibited a wide spectrum of cytotoxicity to allogeneic LcL targets. We conclude that EBV-specific Tc, induced in vitro, consist of a number of clones with respect to restrictions imposed by the major histocompatibility complex. The determinants regulating these restrictions may include not only private HLA antigenic determinants that are defined by the HLA serotyping, but also undefined HLA antigenic determinants.

Antigens, Heterophile↗