Search PubMed⌕ Search

Biomedical subjects

K Sugamura

Publications and source records attributed to K Sugamura.

231 records · Page 13Linked to original sources
PubMed1981

Establishment of human cytotoxic T-cell lines specific for Epstein-Barr virus-transformed autologous cells.

EBV-specific cytotoxic T cells (Tc) induced in vitro have continuously proliferated in vitro for over 9 months. The long-term maintenance of the Tc growth was dependent on periodic supplementation of both irrediated EBV-transformed autologous lymphoblastoid cell line (LCL) cels and conditioned medium. The latter was derived from supernatants of human spleen-cell cultures stimulated with phytohemagglutinin. The cultured Tc maintained significant cytotoxic activity to autologous LCL cells but not to EBV-unrelated target cells, including K-562, B-, T-, null-cell lines and mitogen-stimulated antologous peripheral blood lymphocytes. Thus, established EBV-specific Tc lines from five different individuals always exhibited highly significant cytotoxicity against exhibited highly significant cytotoxicity against autologous LCL cells but not always against allogeneic LCL cells. Furthermore, restriction of the Tc to the autologous LCL was more pronounced after long-term culture than it was initially. This suggests that certain clones of Tc which arignificant cytotoxicity against exhibited highly significant cytotoxicity against autologous LCL cells but not always against allogeneic LCL cells. Furthermore, restriction of the Tc to the autologous LCL was more pronounced after long-term culture than it was initially. This suggests that certain clones of Tc which arignificant cytotoxicity against exhibited highly significant cytotoxicity against autologous LCL cells but not always against allogeneic LCL cells. Furthermore, restriction of the Tc to the autologous LCL was more pronounced after long-term culture than it was initially. This suggests that certain clones of Tc which are probably restricted to HLA are selectively established during long-term cultivation.

Antigens, Viral↗
PubMed1981

T cell growth factor from human splenic cell cultures: conditions for its production, and its utilization for maintenance of cytotoxic T cell lines.

We prepared the T cell growth factor (TCGF) from human spleen cell cultures stimulated with phytohemagglutinin (PHA). Various cell culture conditions and agents supporting the active TCGF production of the spleen cells were examined. The highest TCGF activity was obtained in the supernatants under the conditions that 2 x 10(6)/ml spleen cells were stimulated with PHA for 48 hr. Production of TCGF from spleen cells depended markedly on their individual sources. Addition of indomethacin to the culture or irradiation of the responding spleen cells increased TCGF activity in the supernatant of the culture. Further, addition of irradiated cells of an Epstein-Barr virus (EBV)-transformed lymphoblastoid cell line (LCL) to spleen cell cultures stimulated with PHA greatly enhanced TCGF production. Human splenic TCGF facilitated the establishment of human cytotoxic T cell (Tc) lines specific for EBV-transformed LCL cells when those Tc line cells were stimulated periodically with irradiated autologous LCL cells but not with the other two types (K-562 or Molt-4) of cells. Allogeneic LCL stimulators allowed the Tc line cells to proliferate. However, Tc line cells cocultured once with allogeneic LCL stimulators no longer exhibited EBV-specificity in their cytotoxicities.

Cell Division↗
PubMed1980

Memory of Epstein-Barr virus-specific cytotoxic T cells in normal seropostive adults as revealed by an in vitro restimulation method.

Peripheral blood lymphocytes (PBL) from healthy adults responded with proliferation when stimulated in vitro with lymphoblastoid cell lines (LCL) transformed by Epstein-Barr virus (EBV). Proliferation was not dependent on EBV-serologic status of the PBL donors. After 4 times stimulation with the autologous LCL, viable cells recovered from the cultures consisted mainly of T cells in both EBV-seropositive and seronegative individuals. However, the effector functions of T cells from these 2 groups differed. The effector cells generated from PBL of the seropositive group were cytotoxic to autologous LCL cells, but those from the EBV-seronegative group showed little lysis against autologous LCL cells. These results indicate that the EBV-specific cytotoxic T cells (Tc) can be induced in vitro from seropositive but not seronegative individuals. On the other hand, EBV-nonspecific effector cells detected by K-562 target cell lysis were derived from cultures from both the seropositive and seronegative individuals, especially after the first and second stimulations. Lysis of K-562 targets decreased, however, after the third and fourth restimulation. In 56 effector-target combinations, EBV-specific Tc induced always lysed autologous LCL cells more effectively than allogeneic LCL cells. These data together with HLA-typing results suggested a possibility of the HLA-A or -B restriction of the EBV-specific Tc.

Cell Division↗
PubMed1978

Involvement of fusion activity of ultraviolet light-inactivated Sendai virus in formation of target antigens recognized by cytotoxic T cells.

Mice inoculated with ultraviolet light-inactivated Sendai virus mount a cell- mediated immune response to the virus. Cytotoxic T cells specific for Sendai virus can be obtained by in vitro secondary stimulation of primed spleen cells with syngeneic stimulator cells coated with UV-inactivated Sendai virus. Neither in vivo nor in vitro stimulation alone is sufficient to generate specific cytotoxic T cells. Sharing of the H-2 haplotype between cytotoxic T cells and target cells is required for the Sendai virus-specific lysis to occur. The fusion (F) glycoprotein of Sendai virus has been implicated in target antigen formation (20). Ethanol treatment of Sendai virus causes complete inactivation of the cell-fusion and hemolytic activities of the envelope, but does not affect the antigenicity of the F glycoprotein; furthermore, hemagglutinin and neuraminidase activities of the envelope HANA glycoprotein are also left intact after ethanol treatment. Target cells can be prepared by coating them with various numbers of UV-inactivated Sendai virus that have been treated with ethanol or, as a control, phosphate-buffered saline (PBS). The amount of virus adsorbed to target cells during the cytotoxicity reaction time using either ethanol-treated or untreated (PBS "treated") virions is essentially identical, but target cells coated with ethanol-treated Sendai virus fail to serve as targets for cytotoxic T cells. These results indicate that fusion activity of the Sendai virus envelope is essential to the formation of the target antigen and that virus adsorption to cell surfaces without fusion of the envelope with cell membranes is not sufficient to allow killing by virus-specific cytotoxic T cells.

Animals↗
PubMed1976

Purification and characterization of human liver specific F antigen.

This paper reports the properties of purified human F antigen (liver-specific antigen). Homogenates of liver in 0-25 M sucrose were centrifuged at 105,000 g. The supernatants were chromatographed on Sepharose 6-B and four major peaks were separated. The third peak proved to be predominantly F antigen. This fraction was subsequently subjected to DEAE-cellulose column chromatography and F antigen was eluted at a concentration less than 0-2 M NaCl in 0-01 M sodium phosphate buffer (pH 7-2). Finally, purified F antigen was obtained after preparative isoelectric focusing. Purified human F antigen was found to have a mol. wt between 40,000 and 80,000, a pI of 6-5-6-7 and a density of 1-26. It is a protein antigen and contains no detectable carbohydrate or lipid. No differences were found in purified F-antigen preparations from several species when tested by sodium dodecyl sulphate (SDS) disc gel electrophoresis. Immunofluorescent studies showed that F antigen was homogeneously distributed in the cytoplasm of liver cells but was not present on the cell surface. Immunization of guinea-pigs with purified human liver-specific protein did not induce antibody to the F antigenic determinant defined by mouse anti-F antiserum. It did, however, induce antibodies to two human liver antigens. One of these seems to be a human-specific determinant on the F antigen molecule and the other appears to be a separate molecule which is similar in molecular weight and electrophoretic mobility to the F-antigen molecule.

Animals↗
PubMedDate not supplied

Regulation of CD3- lymphocyte function with an antibody against the IL-2 beta chain receptor: modulation of NK and LAK activity and production of IFN gamma.

To elucidate the role of interleukin 2 (IL-2) activation in CD3- lymphocytes, we examined the ability of monoclonal antibody (MAb) TU27, developed against the IL-2 receptor (IL-2R) p75 protein (IL-2R beta), to block lymphocyte activation with exogenous IL-2, as well as its innate ability to activate lymphocytes as a result of its surface ligand interaction. The binding of the TU27 MAb and the results of 125I-IL-2 cross-linking experiments suggest that the IL-2R beta chain is expressed primarily on CD3-, CD56+ lymphocytes; although the protein was also detected in a small portion of CD3+ cells, its expression appeared to be donor dependent. In the present study, we found that TU27 totally blocked natural killer (NK) cell activation in a 4-h assay but had no effect on basal levels of NK activity. When treatment was extended to 24 to 72 h, the MAb was able to block the induction of both NK and lymphokine-activated killer (LAK) activity. Of interest was the observation that MAb treatment alone augmented NK activity and subsequent interferon gamma (IFN gamma) production in CD3- lymphocytes but did not activate LAK activity or induce cell growth. Collectively, these results indicate that TU27 not only reacts with p70-75 IL-2R beta but can abrogate IL-2 binding and subsequent activation events. In addition, some CD3- lymphocyte functions (e.g., NK activity and IFN gamma secretion) are directly induced by the binding of MAb to p70-75 through signals that only partially mimic IL-2.

Antibodies, Monoclonal↗
PubMedDate not supplied

Characterization of imidazopyrroloquinoline compounds synthesized from coenzyme PQQ and various amino acids.

Imidazopyrroloquinoline (IPQ) compounds synthesized from coenzyme PQQ (pyrroloquinoline quinone) and various kinds of amino acids were characterized. IPQ was synthesized from coenzyme PQQ and one of three amino acids (glycine, L-tryptophan and L-tyrosine). Two kinds of IPQ compound were formed from coenzyme PQQ and L-serine. At higher pH, IPQ was synthesized, at lower pH hydroxy-methyl-IPQ was synthesized. IPQ with R of amino acids represented by R-CH(NH2)-COOH was synthesized from coenzyme PQQ and other amino acids. IPQ compounds do not act as cofactor of glucose dehydrogenase. Molar absorption coefficients of IPQ are 31,400 M-1 cm-1 at 251 nm, 30,700 M-1 cm-1 at 276 nm, and 20,700 M-1 cm-1 at 423 nm at pH 7.0 and room temperature.

Amino Acids↗
PubMedDate not supplied

Randomized comparison of two preoperative methods for preparation of the colon: oral administration of a solution of polyethylene glycol plus electrolytes and total parenteral nutrition.

BACKGROUNDS/AIMS: Two colon preparation methods were compared for their efficacy. The comparison was carried out between whole bowel irrigation using polyethylene glycol-electrolyte lavage solution (PEG-ELS) and total parenteral nutrition (TPN). METHODOLOGY: Twenty-six consecutive patients suffering from colorectal cancer without apparent obstruction were randomly divided into two groups. Twelve patients received 2 litres of PEG-ELS one day before the operation following two tablets of sennoside (24 mg) two days before the operation without restriction of food until PEG-ELS. Fourteen patients received magnesium citrate (34 g) and sennoside (24 mg) on the day before the operation with 7 days' TPN and fasting. RESULTS: The average time of defecation was 9 in the PEG-ELS group and 5 in the TPN group (p < 0.001), with little difference between the necessary times to complete defecation (PEG-ELS: 280 min. vs. TPN: 260 min.). However, although half of the PEG-ELS group complained of side effects of abdominal fullness the overall incidence of side effects in both groups were the same of 50%. There were no significant changes between the data of blood test and routine chemistry before and after the bowel preparation in both groups. The purity of the colorectum judged at operation in both groups were excellent, no residue at all, except in one patient of the TPN group. The total bacterial counts of the rectal samples obtained at operation of PEG-ELS group were fewer than that of TPN group but not statistically significant. CONCLUSION: Colon preparation using PEG-ELS is just as good as the 7-days' TPN treatment and fasting, and exceeds from the standpoint of saving time.

Administration, Oral↗