Determinação do efeito mitogênico das lectinas de Cratylia mollis sobre linfócitos humanos utilizando um método colorimétrico

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

Lectins are proteins or glycoproteins that bind to specific saccharides. Several of them exhibit mitogenic activity on lymphocytes in vitro or are toxic in cultured cells. These properties are involved with carbohydrate binding sites. In this work it was determined the mitogenic activity of Cratylia mollis lectins (Cra-Sephadex and Cra-Iso 1) on human lymphocytes through a colorimetric assay that is based upon the reduction of 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium (MTT), through a mitocondrial enzyme tetrazolium-succinate-desidrogenase, in MTT-formazan, which is a dark colored product. The isoforms of C. mollis are purified following a previously established protocol. Lymphocytes were previously isolated from the periferic human blood through a density gradient given by histopaque. Lectin samples (Cra-Sephadex, Cra Iso 1, concanavalina A, Con-A and phytohaemagglutinine, PHA) at different concentrations were utilized in this assay. Subsequently it was performed a mitogenic activity inhibition assay utilizing the carbohydrate methyl α-D-mannoside. The obtained results were expressed as a proliferation index, PI, which stands for the ratio between the proliferation absorbance in the presence and in the absence of the lectin. Both C. mollis lectins are mitogenic and the effects of these lectins are comparable to the mitogenic lectins, such as Con-A and PHA. The inhibition of the lymphocyte proliferation utilizing the binding carbohydrate indicated that these mitogenic effect to be involved to the lectin binding site

ASSUNTO(S)

cratylia mollis bioquimica lectinas método colorimétrico linfócitos humanos

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