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Hideki Ohba

Publications and source records attributed to Hideki Ohba.

4 recordsLinked to original sources
PubMed2003

Synthesis of DNA-peptide conjugates by solid-phase fragment condensation.

[reaction: see text] DNA-peptide conjugates were synthesized by condensing partially protected peptide fragments and oligonucleotides on a CPG support using diisocyanatoalkane as a linker. After cleavage and deprotection with aqueous ammonia, pure products were obtained by single RPHPLC purification in satisfactory yields and identified by a MALDI-TOF MS spectrometer. This method allows one to prepare DNA-peptide conjugates with any components and sequences of DNA and peptides.

Amino Acid Sequence↗
PubMed2003

Relationships between degree of binding, cytotoxicity and cytoagglutinating activity of plant-derived agglutinins in normal lymphocytes and cultured leukemic cell lines.

PURPOSE: To clarify the relationships between the degree of lectin-cell binding, cytotoxicity and cytoagglutinating activity of plant-derived lectins in normal lymphocytes and cultured leukemic cell lines. METHODS: Plant lectins with different quaternary structures and saccharide specificity were used: Dolichos biflorus agglutinin (DBA), Soybean agglutinin (SBA) and Wheat germ agglutinin (WGA). The leukemic cell lines used were: Jurkat, MOLT-4, RPMI-8402, HPB-ALL, CCR-HSB-2 and BALL-1 (derived from acute lymphoblastic leukemia); Raji and Daudi (derived from Burkitt's lymphoma); K-562 (derived from myelogenous leukemia). The lectin-cell binding was detected microscopically and fluorimetrically using FITC-conjugated lectins. Cytotoxicity was estimated by the CellTiter-Glo luminescent cell viability assay, and cytoagglutinating activity by a spectrophotometric method. RESULTS: The binding of DBA and SBA to normal lymphocytes was negligible, while their binding to leukemic cells increased markedly with increasing lectin concentration. Analogous results were obtained for WGA. However, it was found that WGA also interacted to a significant degree with normal lymphocytes. The degree of lectin-cell binding increased in the order: DBA<SBA<WGA. The cytoagglutinating activity and cytotoxicity of lectins increased in the same order. DBA did not exhibit a cytotoxic effect against normal or leukemic cells, and showed a poor cytoagglutinating activity only in MOLT-4, CCR-HSB-2 and BALL-1 cells. SBA exhibited poor cytotoxicity against Jurkat, RPMI-8402, HPB-ALL and CCR-HSB-2 cells, but a well-defined cytotoxicity against Raji and Daudi cells. SBA showed poor cytoagglutinating activity in leukemic cells. In contrast, WGA at concentrations higher than 0.05 microM showed high cytotoxicity against all leukemic cell lines tested as well as against normal lymphocytes. WGA also showed a well-expressed cytoagglutinating effect in all cell lines except normal lymphocytes. There was a moderate inverse correlation between cell viability and the velocity of cytoagglutination ( r=-0.56, P<0.001), and a good correlation between cell viability and the degree of lectin-cell binding ( r=-0.75, P<0.001). There was a low positive correlation between the velocity of cytoagglutination and the degree of lectin-cell binding ( r=0.43, P<0.001). CONCLUSION: The results suggest that the lectins that bound most strongly to leukemic cells expressed higher cytotoxic and cytoagglutinating activities.

Agglutination↗
PubMed2003

Cytoagglutination and cytotoxicity of Wheat Germ Agglutinin isolectins against normal lymphocytes and cultured leukemic cell lines--relationship between structure and biological activity.

The relationships between degree of lectin-cell binding, cytotoxicity and cytoagglutinating activity of three Wheat Germ Agglutinin isolectins (WGA-1, WGA-2, WGA-3) against normal lymphocytes and cultured leukemic cell lines (Jurkat, MOLT-4, Raji, Daudi, K-562) were studied. All WGA-isolectins interacted in a similar degree with normal lymphocytes, while in the case of leukemic cells, the degree of isolectin-cell binding increased in the order: WGA-1< or =WGA-3<WGA-2 at isolectin concentrations 0.5 microM and higher, and WGA-3<WGA-2< or =WGA-1 at 0.25 microM isolectin concentration. The WGA interacted in higher degree with Jurkat, Raji, Daudi and K-562, followed by MOLT-4 and normal lymphocytes. The velocity of cytoagglutination in the presence of 0.25 microM WGA-isolectins increased in the order: WGA-3<WGA-2< or =WGA-1, and was better expressed in Jurkat, Raji, Daudi and K-562, followed by MOLT-4 and normal lymphocytes. The cytotoxicity of isolectins was very well expressed against Jurkat, MOLT-4, Raji and Daudi, and less expressed against K-562 and normal lymphocytes. In the case of leukemic cells, the cytotoxic effect of WGA-isolectins increased in the order: WGA-3<WGA-2=WGA-1. A very good positive correlation was determined between velocity of cytoagglutination and degree of lectin-cell binding (r=0.77, P<0.001). A good inverse correlation was found between cytotoxicity and degree of lectin-cell binding (r=-0.34, P<0.001), and poor correlation was observed between cytotoxicity and cytoagglutinating activity of WGA-isolectins (r=0.16, P<0.01). The results suggest that the WGA-isolectins, structurally distinguishable in only several amino acid sequences, interacted in different degrees with leukemic cells and manifested different cytoagglutinating and cytotoxic activity.

Agglutination Tests↗