Histological immunoenzyme techniques in canine tissues: evaluation of various methods and modifications

Several antigens including immunoglobulin light and heavy chains, C3, macrophage enzymes and various brain proteins were demonstrated immunohistologically in paraffin sections of canine tissues. The indirect immunoperoxidase, the unlabelled antibody enzyme (PAP), double bridging PAP, and biotinavidin-peroxidase (BAP) methods were compared. The influence of various histological procedures such as fixation and embedding, and other modifications such as enzyme treatment of sections was investigated. The best results were obtained with the PAP and BAP methods on formalin fixed tissues. Trypsin proved to be highly effective for demonstrating certain antigens but required firm adhesion of the sections. Prolonged incubation with the primary antisera improved the results considerably. Based on the results of this study a general strategy for solving immunohistological problems has been proposed.