Alcian blue-treated polystyrene microtitre plates for use in an ELISA to measure antibodies against synthetic peptides.

Short peptides often do not bind well to the plastic surface of microtitre wells in solid-phase immunoassays. To improve the reactivity of synthetic peptides coated on the solid phase, we have developed a highly sensitive, rapid and simple ELISA. This ELISA is based on the treatment of microtitre plates with Alcian blue prepared in acetic acid prior to coating the target peptide. With hyperimmune serum, this treatment increases the specific signal in such a manner that the detection of antibodies needs less antigen than with conventional ELISA. Moreover, the Alcian blue treatment was shown to be particularly effective for the detection of monoclonal antibodies against a synthetic peptide derived from the human immunodeficiency type 1 (HIV-1) vpu protein. These monoclonal antibodies that were not detected in conventional ELISA gave a positive signal up to a 1 in 1000 dilution after Alcian blue treatment of microtitre wells. This assay should be applicable to a variety of synthetic peptides and other types of molecules posing problems in assays requiring their immobilization on solid phases.