[Immunohistochemical demonstration of mycobacterial antigen]

BCG antigen and M. tuberculosis antigen were demonstrated in smear of M. tuberculosis, tissue sections of experimental infected mice and tuberculous patients by immunohistochemical staining. Both acid-fast-HRP-SPA and acid-fast-IGSS double staining methods were tried successfully. Both antigens were present on acid-fast bacilli (AFB). Furthermore, BCG antigen was localized on the mycobacteria cell wall by immunoelectron-microscopic staining. Both antigens were not detected in 19 control specimens of normal tissues and the tissues infected by 8 other species bacilli or fungi except M. leprae and atypical mycobacteria (photochromogens). The rate of positive BCG antigen (69.34%, 95/137) was significantly higher than that of AFB (34.3%, 47/137), (P less than 0.01). The antigens were also found in some AFB free necrotic areas and macrophages. So, immunohistochemical detection of mycobacteria antigens is fairly specific. It is helpful in studying immunopathological changes and in the diagnosis of tuberculosis.