Indirect immunofluorescence labelling with complexes of phycoerythrin and monoclonal anti-phycoerythrin antibodies (PEAPE complexes)

Abstract We describe a method of immunofluorescence which is a lateral application of the principles of the APAAP immunohistochemical technique. Immune complexes of R-phycoerythrin and monoclonal anti-R- phycoerythrin (PEAPE complexes) were used in an indirect immunofluorescence technique to detect the binding to cells of monoclonal antibodies directed to IgM, HLA-DR and B cell activation and differentiation antigens. PEAPE complexes were linked to cell surface bound mAbs by unlabelled anti-mouse Ig antibodies to produce high levels of fluorescent staining. The sensitivity of this method of indirect immunofluorescence was enhanced by the sequential application of several cycles of anti-mouse Ig and PEAPE complexes.