A method is described which permits the adaption of ELISA techniques for measurement of antibody against bacterial polysaccharides. First, the polysaccharides antigen is covalently bound to poly-L-lysine, using cyanuric chloride as the coupling agent. The poly-L-lysine then adsorbs to the walls of plastic tubes, thus immobilizing the polysaccharide coupled to the poly-L-lysine. The method is simple, rapid, and utilizes small amounts of polysaccharide antigen.