Binding of oxidized Jurkat cells to THP-1 macrophages and antiband 3 IgG through sialylated poly-N-acetyllactosaminyl sugar chains

Human T-lymphoid cell line Jurkat cells were mildly oxidized with diamide, hydrogen peroxide, or t-butyl-hydroperoxide. The recognition of Jurkat cell s in the absence of serum by human monocytic leukemia cell line THP-1 diffe rentiated into macrophages was enhanced by the oxidation with these reagent s. The recognition was maximal when Jurkat cells were treated with each of the reagents at the relatively low concentrations, and the recognition was decreased on treatment with the reagents at the higher concentrations. The enhanced recognition of THP-1 macrophages to diamide-oxidized Jurkat cells was lowered when the binding was conducted in the presence of the oligosacc harides fi om band 3 glycoprotein and lactoferrin. The inhibitory effect of band 3 oligosaccharides was abolished by removal of the non-reducing-termi nal sialyl residues or by cleavage of poly-N-acetyllactosaminyl sugar chain s in the saccharides. Moreover, on enzymatic removal of the non-reducing-te rminal sialyl residues or enzymatic cleavage of the poly-N-acetyllactosamin yl sugar chains on the surface of Jurkat cells prior to oxidation, the cell s mere recognized poorly by THP-1 macrophages. Human naturally occuring ant iband 3 IgG bound effectively to the hydrogen peroxide-oxidized Jurkat cell s. This binding was abolished by the enzymatic cleavage of the poly-N-acety llactosaminyl sugar chains on the surface of the cells prior to oxidation w ith hydrogen peroxide. The results indicate that binding of TBP-I macrophag es and antiband 3 IgG to Jurkat cells was increased by mild oxidation of Ju rkat cells, and the bindings were through sialylated poly-N-acetyllactosami nyl sugar chains on Jurkat cell surface. (C) 2000 Academic Press.