419 resultados para reductive paraphrase
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The induction of CD8+ cytotoxic T lymphocytes (CTLs) is desirable for immunization against many diseases, and recombinant-synthetic peptide antigens are now favored agents to use. However, a major problem is how to induce CTLs, which requires a T1-type response to such synthetic antigens. We report that T1-type (generating high CTL, low antibody) or T2-type (the reciprocal) responses can be induced by conjugation of the antigen to the carbohydrate polymer mannan: T1 responses are selected by using oxidizing conditions; T2 responses are selected by using reducing conditions for the conjugation. Using human MUC1 as a model antigen in mice, immunization with oxidized mannan-MUC1 fusion protein (ox-M-FP) led to complete tumor protection (challenge up to 5 x 10(7) MUC1+ tumor cells), CTLs, and a high CTL precursor (CTLp) frequency (1/6900), whereas immunization with reduced mannan-MUC1 FP (red-M-FP) led to poor protection after challenge with only 10(6) MUC1+ tumor cells, no CTLs, and a low CTLp frequency (1/87,800). Ox-M-FP selects for a T1 response (mediated here by CD8+ cells) with high interferon gamma (IFN-gamma) secretion, no interleukin 4 (IL-4), and a predominant IgG2a antibody response; red-M-FP selects for a T2-type response with IL-4 production and a high predominant IgG1 antibody response but no IFN-gamma.
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In the present Letter several carbolactones (oxidative products) are obtained under aprotic cathodic conditions in the preparative scaled electrolysis of 1,2-quinones in a divided electrochemical cell and in the presence of oxygen. When 9,10-phenanthrenequinone is reduced 6H-dibenzo[b,d]pyran-6-one and [1,1′-biphenyl]-2,2′-dicarboxylic acid are obtained as major products. In the reduction of 1,2-naphthoquinone, 2-benzopyran-1(1H)-one, and 2-(2-carboxyethenyl)-benzoic acid were formed as main products. The proposed mechanism to explain the formation of these and other products, that involves an electron-transfer reaction to the oxygen in air, is now discussed.
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The reaction of various 1-pivaloyl-1H-tetrazoles with excess lithium and a catalytic amount of naphthalene (20 mol%) led, after treatment with methanol, to the corresponding free tetrazoles through reductive C–N bond cleavage. This methodology represents a reasonable alternative to other nonreductive protocols.
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Mode of access: Internet.
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Includes bibliographical references and index.
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Mode of access: Internet.
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Mode of access: Internet.
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Caption title.
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Mode of access: Internet.
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Edited by Job Orton.
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Mode of access: Internet.