Demonstration of various antigens on paraffin sections of formalin-fixed tissues: trypsin-treated, indirect peroxidase-labelled antibody technique.

Detection of various antigens was performed on the formalin-fixed, paraffin-embedded sections by indirect peroxidase-labelled antibody technique after pretreatment with trypsin digestion. It was revealed that the optimal condition for trypsin digestion of the paraffin sections differed according to the character of antigen and type of tissue, and, under the optimal condition, this method was easily applicable to the regular paraffin sections obtained in the laboratories for routine examinations. This method was also recommended for the detection of the antigens which were usually stained even without trypsin digestion, since it could not only remove the background staining but also uncover the otherwise masked antigen.