Detection of AB antigen in blood stain using enzyme-linked immunosorbent assay

A new method for detection of AB antigen from blood stain using enzyme-linked immunosorbent assay (ELISA) is described. Flat-bottomed-wells of polystylen plate coated with human anti-B or rabbit anti-A were sensitized with AB antigen which was extracted from blood stain with 1% octyl-glucopyranoside in 0.1 M phosphate buffer pH 8.0. Mouse monoclonal anti-A or anti-B, and peroxidase conjugated anti-mouse immunoglobulin were added to the wells, respectively. Subsequently, the substrate was dropped into the wells, and the absorbance of the solution was measured. By this method, we could distinguish AB group blood stain from the mixed stain of A and B group bloods. When rabbit antiserum was used as the first antibody, differentiation between these antigens was unsuccessful presumably because of non-specific adsorption.