Monoclonal Antibodies Directed to the Synthetic Carbohydrate Antigen Le y

Abstract

ABSTRACT

Tetrasaccharide Fucα1-2Galβ1-4(Fucα1-3)GlcNAc is known as carbohydrate determinant of cancer- and AIDS-associated antigen Lewis^y (Le^y). Synthetic antigen to generate mouse monoclonal antibodies (MAbs) directed to Le^y was prepared and constructed as a spacer-armed tetrasaccharide coupled with lipophilized polymer, Le^y-PAA-PE, where PAA is a 30-kD polyacrylamide and PE is phosphatidylethanolamine. An efficient immune response was provided by using Le^y-PAA-PE adsorbed on Salmonella minnesota. Positive hybridomas were screened by enzyme-linked immunosorbent assay (ELISA) using Le^y-PAA as a coating agent. An inhibitory version of the same test system showed absolute specificity of two MAbs: only hapten Le^y and Le^y-PAA were strong inhibitors, in contrast to Le^b, tri- and disaccharidic fragments of the mentioned tetrasaccharides, as well as their PAA-conjugates. MAbs obtained against synthetic antigen specifically stained the Le^y(+) cell line A431.