Detection of chicken anaemia agent in chickens by immunofluorescence and immunoperoxidase staining

An immunofluorescent method for the detection of CAA antigens in impression smears and cryostat sections of bone marrow and thymus tissue from infected birds is described. CAA antigens were detected using both rabbit and chicken antisera to the virus. A protocol for the demonstration of CAA antigens in formalin-fixed, paraffin-embedded thymus tissue, using a biotin-streptavidin peroxidase detection system, was also developed. Treatment of tissue sections with eleven protease solutions, prior to application of primary antibody, was evaluated. Only protease types III and XIV were successful in unmasking CAA antigens while preserving good tissue morphology with no non-specific background staining.