ENZYME IMMUNOHISTOCHEMISTRY WITH MONOCLONAL AND POLYCLONAL ANTIBODIESIN THE PATHOLOGICAL DIAGNOSIS OF SYSTEMIC BOVINE MYCOSES

To improve the immunohistopathological diagnosis of systemic bovine my coses we have evaluated the utility of antifungal polyclonal and monoc lonal antibodies, and peroxidase and alkaline phosphatase staining tec hniques. A rabbit polyclonal antibody to mannan from Candida albicans was specific for candidosis. The diagnosis of aspergillosis was accomp lished using a rat monoclonal antibody to the galactofuran side chains of Aspergillus galactomannan. A murine monoclonal antibody reacting w ith weakly Con-A binding 41 and 46 kDa somatic antigens from Absidia c orymbifera was used for immunostaining of zygomycetic hyphae. Peroxida se antiperoxidase (PAP) and alkaline phosphatase antialkaline phosphat ase (APAAP) complexes were visualized using aminoethylcarbazole and fa st red substrates. A green staining of PAP reactions with dioctyl sulf osuccinate sodium and 3,3',5,5'-tetramethylbenzidine (DONS/TMB) was ef fective for the demonstration of fungi in dual and triple infections. Tissue sections of experimentally infected mice were used to determine the sensitivity and specificity of the antibodies. Tisssues obtained from 161 bovine mycotic lesions previously studied by indirect immunof luorescence staining were further evaluated using the three antibodies . In all of 45 lesions solely affected by aspergillosis and in three s olely affected by candidosis the diagnoses were confirmed by the new e valuation. In 85 of 96 cases of single infections with zygomycetes the diagnosis was confirmed, while none of the antibodies reacted with fu ngal elements in the remaining 11 lesions. Aspergillus hyphae were det ected in all three lesions with dual aspergillosis and zygomycosis, wh ereas zygomycetic material was confirmed in only two of these cases. A mixed infection of candidosis and zygomycosis in a lymph node was con firmed too. In 13 cases in which a diagnosis had not hitherto been obt ained, aspergillosis and zygomycosis were recorded each in three cases .