Isolation of the receptor for the Amaranthus leucocarpus lectin from human T lymphocytes.

Flor Porras, Francisco Urrea, Blanca Ortiz, Salvador Martínez-Cairo, Stéphane Bouquelet, Gisela Martínez, Ricardo Lascurain, Edgar Zenteno

Departamento de Bioquímica, Instituto Nacional de Enfermedades Respiratorias, Calzada de Tlalpan 4502, 01040, Mexico.

Biochimica et biophysica acta 2005 Jun 20

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Amaranthus leucocarpus lectin (ALL) is specific for GalNAc, and recognizes human T cells. The receptor for ALL was purified from T cells using biotin-labeled lectin and avidin-agarose as affinity matrix. It is a 70-kDa glycoprotein, constituted mainly by serine, glycine, and glutamic acid; its glycosidic portion contains mainly GalNAc; galactose, sialic acid, mannose, and GlcNAc were identified at a lower proportion. By ionic strength chromatography, as well as double dimension electrophoresis, we identified four isoforms of the ALL-receptor. N-terminal amino acid was blocked both in the ALL-receptor and its isoforms, therefore, tryptic peptides of ALL-receptor, analyzed through MALDI-TOF, were compared with the relative values obtained from the NCBInr (ProFound 2004/06/01) database. Our results indicated that the tryptic peptides obtained showed 54% homology with a DnaK-core molecular chaperone, 47% with human KIAA protein, and 44% with heat shock protein 8. The most frequent phenotype of the CD4 or CD8 ALL+ T cells was CD45RA+ CD27+; 26% of ALL+ T cells were CD25+ and 13% were CD69+, indicating that the glycoprotein recognized by ALL is present mainly on naive or quiescent T cells.

Citation

Flor Porras, Francisco Urrea, Blanca Ortiz, Salvador Martínez-Cairo, Stéphane Bouquelet, Gisela Martínez, Ricardo Lascurain, Edgar Zenteno. Isolation of the receptor for the Amaranthus leucocarpus lectin from human T lymphocytes. Biochimica et biophysica acta. 2005 Jun 20;1724(1-2):155-62