AN IMMUNOHISTOCHEMICAL METHOD OF DETECTING MYCOPLASMA SPECIES ANTIGENS BY USE OF MONOCLONAL-ANTIBODIES ON PARAFFIN SECTIONS OF PNEUMONIC BOVINE AND CAPRINE LUNGS

Lung samples from pneumonic lesions in cattle and goats, naturally or experimentally infected with strains of the Mycoplasma mycoides cluste r, were fixed in formalin and embedded in paraffin. An immunohistochem ical technique using monoclonal or polyclonal antibodies was performed on tissue sections in order to detect Mycoplasma antigens. Four monoc lonal antibodies (MAbs), one (2A3) raised against M. mycoides ssp. myc oides small colony (SC) and large colony (LC), two (1D3 and 5E5) again st M. mycoides ssp. capri, and one (5A10) against M. bovis, were used. A range of polyclonal antibodies, raised to the individual subspecies of the M. mycoides cluster, and one to Pasteurella haemolytica, was a lso used. The MAb 2A3 showed positive immunostaining in lung sections from cattle and goats naturally and experimentally infected with M. my coides ssp. mycoides SC and LC, but not with pneumonic lesions of catt le and goats due to other members of the M. mycoides cluster, M. bovis or Pasteurella spp. The MAb 1D3 showed immunostaining in lung section s from goats naturally and experimentally infected with M. mycoides ss p. capri, but again not with pneumonic lesions caused by other members of the M. mycoides cluster, M. bovis or Pasteurella spp. The MAb 5E5 immunoreacted in sections from pneumonic lesions from all animals infe cted with one of the three M. mycoides cluster subspecies used in the study, but not with M. bovis or Pasteurella infected tissue. Immunorea ction was mainly found in the cell debris around necrotic areas, as we ll as in macrophages, neutrophils and epithelial cells. The localizati on of antigens of the M. mycoides duster using polyclonal antisera fol lowed basically the same pattern as that obtained with the monoclonals . However, a wide cross reactivity was found between different antiser a and relatively high background immunostaining was also seen, especia lly in necrotic areas. The results suggest that immunohistochemical me thods using monoclonal antibodies are useful tools for the diagnosis a nd study of the pathogenesis of pneumonia caused by the Mycoplasmas of the M. mycoides cluster.