A comparison of immunoferritin, immuno-enzyme and gold-labelled protein A methods for the localization of capsular antigen on frozen thin sections of the bacterium, Pasteurella haemolytica.

The staphylococcal protein A-gold method was found to be superior to the enzyme-or ferritin-linked antibody techniques for locating capsular antigens on cryosections of Pasteurella haemolytica, and its sensitivity was similar to the enzyme-linked antibody method. The sensitivity of conventionally fixed and embedded material and cryosections of heavily fixed, lightly fixed and unfixed material were shown to be similar under routine laboratory conditions.