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Biomedical subjects

Y Ichimori

Publications and source records attributed to Y Ichimori.

31 records · Page 2Linked to original sources
PubMed1990

A human hybrid hybridoma producing a bispecific monoclonal antibody that can target tumor cells for attack by Pseudomonas aeruginosa exotoxin A.

By fusing a human hybridoma producing an IgG2 kappa antibody against human A431 epidermoid carcinoma cells with an Epstein-Barr virus-transformed human B lymphocyte producing an IgG2 kappa antibody against Pseudomonas aeruginosa exotoxin A, we established a hybrid hybridoma producing a bispecific monoclonal antibody reacting with both A431 cells and the exotoxin. Human IgG was purified from the culture supernatant of the hybrid hybridoma, and the bispecific monoclonal antibody in the IgG preparation was further separated from the two parental antibodies by hydroxyapatite high-performance liquid chromatography. The human bispecific monoclonal antibody thus obtained efficiently targeted the antibody-reactive cells, A431, for attack by the exotoxin in vitro.

ADP Ribose Transferases↗
PubMed1990

A human-human hybridoma secreting anti-Pseudomonas aeruginosa exotoxin-A monoclonal antibody with highly potent neutralizing activity.

A hybridoma secreting human monoclonal antibody (MAB) against Pseudomonas aeruginosa exotoxin A (PEA) was constructed by fusing Epstein-Barr virus-transformed peripheral blood lymphocytes with human B lymphoblastoid cell line TAW-925. The human-human hybridoma stably produced human IgG2 MAB at the rate of 0.4-0.5 microgram/ml per 10(6) cells per day for more than six months, and the MAB was capable of neutralizing the in vitro cytotoxic and in vivo lethal effects of PEA with approximately 100- and 70-fold, respectively, higher activity than serum polyclonal antibody preparations.

ADP Ribose Transferases↗
PubMed1987

Establishment of hybridoma secreting human monoclonal antibody against hepatitis B virus surface antigen.

The HAT (hypoxanthine, aminopterin, thymidine) sensitive and ouabain resistant human B lymphoblastoid cell line TAW-925 was obtained from 6-thioguanine resistant B lymphoblastoid cell line WI-L2. Hybridomas were obtained at a high frequency (10(-4)-10(-5) when TAW-925 was hybridized with cells transformed with Epstein-Barr virus. Using TAW-925 as a parental cell line, we have obtained a hybridoma which stably secretes human monoclonal antibody against hepatitis B virus surface antigen.

Antibodies, Monoclonal↗
PubMed1987

Monoclonal antibodies to human interferon-gamma. II: Antibodies with neutralizing activity.

Two types of hybridomas secreting monoclonal antibodies (MAB) with neutralizing activity against human interferon-r (HuIFN-r) were obtained by somatic cell hybridization between mouse myeloma P3UI cells and spleen cells from BALB/c mice immunized with purified recombinant HuIFN-r and a conjugate of a synthetic amino-terminal peptide (residues 4-21) of HuIFN-r and bovine thyroglobulin. One of these MAB recognized the amino-terminal region (residues 4-21) of HuIFN-r, and the other recognized some region in the internal part (residues 22-130) of the molecule. These results suggest that another region, in addition to the amino-terminal region, contributed to the biological activity of rHuIFN-r. A combination of one of these MAB and a previously described MAB directed to the carboxyl-terminal region (residues 131-146) of HuIFN-r enables a quantitative and sensitive assay method of biologically active rHuIFN-r.

Antibodies, Monoclonal↗
PubMed1987

Differential purification by immunoaffinity chromatography of two carboxy-terminal portion-deleted derivatives of recombinant human interferon-gamma from Escherichia coli.

Two lower-molecular-weight derivatives of recombinant human interferon-gamma (rIFN-gamma) were purified concurrently from a lysozyme-EDTA extract of Escherichia coli cells by immunoaffinity chromatography using a monoclonal antibody (MAb) against a synthetic carboxy-terminal peptide (Lys-131-Gln-146). The two derivatives, 15K rIFN-gamma and 17K rIFN-gamma, were regarded to have been generated at the extraction step. They were successfully separated from each other by using another MAb against the same synthetic peptide with higher binding affinity than the first. The results of protein-chemical analyses indicate that 15K rIFN-gamma and 17K rIFN-gamma lack 15 (Arg 132-Gln-146) and 4 (Arg-143-Gln-146) carboxy-terminal amino acid residues, respectively. All the data suggest that the two derivatives form a noncovalent dimer and that 15K rIFN-gamma binds indirectly to the MAb column via 17K rIFN-gamma.

Amino Acids↗
PubMed1987

Monoclonal antibodies against rat brain protein kinase C and their application to immunocytochemistry in nervous tissues.

Three monoclonal antibodies were prepared against rat brain soluble protein kinase C. Two of the antibodies, CKI-97 (IgG2b subclass) and CKII-90 (IgG1 subclass), showed weak binding to native protein kinase C. The third antibody, CKI-33 (IgG2b subclass), showed no binding. However, the mixture of CKI-97, CKII-90, and CKI-33 exhibited much stronger binding activity to this protein kinase than any of the antibodies alone. Although none of these antibodies showed protein kinase C-neutralizing activity, Western blot analysis indicated that these antibodies reacted specifically with protein kinase C, presumably its subspecies, that is present predominantly in nervous tissues. Immunocytochemical studies shows that these antibodies can be used for identification of this enzyme in nervous tissues. In rat Purkinje cells, the immunoreactive material was present throughout the cytoplasm, including dendrites and axons, but was poorly represented in the cell nucleus. In cerebellum, the localization of protein kinase C appears to be very similar to that of cGMP-dependent protein kinase.

Animals↗
PubMed1986

Immunologic and molecular characterizations of T cell-derived T cell activating factor.

Culture supernatants from several subclones of a human T hybrid line (24A) stimulated with PMA showed co-stimulatory activity in the proliferation of Con A-stimulated murine thymocytes, but did not show any IL 2 activity. Some subclones did not show co-stimulatory activity even when stimulated with PMA, excluding the possibility of a carry-over effect. The factor found in the culture supernatants increased IL 2 production in normal T cells stimulated with a suboptimal concentration of PHA. The factor also induced IL 2 production in a T hybrid clone, T-394.1, when the latter was stimulated with a suboptimal concentration of mitogens, indicating a direct effect by this T cell-derived factor on mitogen-stimulated T cells inducing IL 2 production. This factor also induced the generation of other lymphokines such as BCDF and IFN-gamma. Northern blot analysis showed that the factor induced an increase in mRNA for IL 2 as well as IL 2 receptor. These results indicated that T cells could secrete a factor with IL 1-like activity. However, Northern blot analysis showed that mRNA from a T hybrid clone does not cross-react with cDNA for IL 1 (beta) derived from human monocytes.

Animals↗
PubMed1985

Monoclonal antibodies to human interferon-gamma. I. Antibodies to a synthetic carboxyl-terminal peptide.

Two types of hybridomas secreting monoclonal antibodies (MAB) against human interferon-gamma (HuIFN-gamma) were obtained by somatic cell hybridization between mouse myeloma P3U1 cells and spleen cells from BALB/c mice immunized with a conjugate of a synthetic carboxyl-terminal peptide (residues 131-146) of HuIFN-gamma and bovine thyroglobulin. One of the antibodies bound to recombinant HuIFN-gamma produced in E. coli as well as to natural HuIFN-gamma, while the others bound only to recombinant HuIFN-gamma. These 2 types of MAB did not neutralize the anti-viral activity of HuIFN-gamma. They were useful for effectively purifying recombinant HuIFN-gamma and quantitatively determining it by an enzyme-linked immunosorbent assay.

Animals↗
PubMed1985

Establishment of hybridomas secreting human monoclonal antibodies against tetanus toxin and hepatitis B virus surface antigen.

Mouse-human heterohybrids (M X H) were constructed and compared with other cell lines (human or mouse) as parental cells to obtain hybrids secreting human monoclonal antibody (MoAb). One of the M X H lines, HM-5, was far superior to the others and useful for establishing hybrids secreting human MoAb. Using HM-5 as a parental cell line, we have obtained 2 hybrids secreting human anti-tetanus toxoid MoAb with neutralizing activity and a hybrid secreting human anti-hepatitis B virus surface antigen (HBsAg) MoAb which recognizes the a-determinant of HBsAg.

Animals↗
PubMed1985

Establishment of hybridomas secreting monoclonal antibodies against C epsilon 2 and C epsilon 4 domains of human IgE.

Three kinds of hybridomas secreting monoclonal antibodies (MAbs) against the epsilon chain of human IgE were constructed by somatic cell hybridization between mouse myeloma P3U1 cells and spleen cells from BALB/c mice immunized with human IgE purified from the culture supernatant of U-266 cells. These MAbs were used effectively for the purification and determination of human IgE. The recognition site in the IgE molecule of each antibody was examined by using various epsilon chain fragment peptides produced in Escherichia coli. From these experiments, it was suggested that one recognized C epsilon 2 and the second C epsilon 4. The third did not recognize the C epsilon 1-C epsilon 4 domains of the recombinant epsilon chain from E. coli, although it bound to the epsilon chain of natural human IgE.

Animals↗
PubMed1984

Correlation of interferon gamma inducing ability to sugar binding specificities of various lectins.

Various lectins were examined to determine possible induction of gamma interferon (IFN-gamma) in human leukocytes. Among the seven positive lectins (Concanavalin A, pea lectin, lentil lectin, rice bran agglutinin, pokeweed mitogen, wheat germ agglutinin, phytohemagglutinin-P), six except rice bran agglutinin belonged to those which recognize carbohydrate chains connected to polypeptide through a glycosylamine linkage between N-acetylglucosamine (GlcNAc) and asparagine residues. The specificity of carbohydrate chain recognition of rice bran agglutinin, residual one positive lectin, has not been reported. Induction of IFN-gamma by wheat germ agglutinin, one of the positive lectins, was inhibited by the addition of GlcNAc during the induction, but not by the addition of glucose, galactose, alpha-methylmannose, N-acetylgalactosamine, N-acetylmannosamine, and lactose.

Binding Sites↗
PubMedDate not supplied

Enhancers of the non-peroxidative metal porphyrin chemiluminescence reaction.

Metal porphyrins catalyse luminol chemiluminescence at pH13 without added peroxide. The effects of 22 different surface active compounds on this reaction were studied using six metal porphyrins and one metal porphyrin conjugate. The most active catalyst was Mn-meso-tetra(4-sulphonatophenyl)porphine. Tween-20 enhanced the activity of this catalyst best at a Tween-20 to luminol ratio of 74:1. However, lauryl sulphate enhanced best at an optimum lauryl sulphate to luminol ratio of over 1000:1 and both detergents enhanced the reaction when present below their critical micelle concentrations. Negatively charged aliphatic compounds such as fatty acids enhanced the reaction but positive-charged aliphatic compounds inhibited it. Small differences in enhancer structure resulted in differing enhancement. For example, linoleic acid enhanced Mn-meso-tetraphenyl porphine more than 10-fold, yet linolenic acid inhibited this catalyst. Conjugation of a metal porphyrin to antibody did not influence its enhancement by detergents. The results indicate that the enhancement mechanism does not require formation of pure detergent micelles but that direct association between enhancer and catalyst may be important.

Hydrogen-Ion Concentration↗