Detection of antibodies against membrane-glycoproteins of swine erythrocytes after experimental infection with Mycoplasma hyopneumoniae

Occurrence of autoantibodies to cilia in lambs with a 'coughing syndrome'

A respiratory disease of lambs that has been termed the 'coughing syndrome' has been observed in the mid-western region of the United States of America. Mycoplasma ovipneumoniae (M. ovipneumoniae) and Mycoplasma arginini (M. arginini) were routinely isolated from the respiratory tract of lambs with this disease. A high level of antibodies reactive with ovine cilia of the upper respiratory tract was detected in the sera from many of the lambs in affected flocks but not in sera of lambs from unaffected flocks. The reactivity of these antibodies with cilia was demonstrated by ELISA and confirmed by indirect immunofluorescent staining and western immunoblotting. These antibodies were predominantly of the IgG isotype. They were distinct from cold or warm agglutinins and could be absorbed from the sera with cilia but not with antigens of common bacterial pathogens of the sheep respiratory tract including M. ovipneumoniae, M. arginini, Pasteurella haemolytica, Pasteurella multocida or Neisseria ovis. In addition, their occurrence appeared to be independent of the specific antibodies to M. ovipneumoniae and M. arginini. Western immunoblotting indicated that the antibodies were directed primarily against an antigen with apparent molecular weight of 50 kDa. In one flock from which serial serum samples were collected from the same lambs over a 10-month period, antibodies to ovine cilia developed before the onset of the clinical disease and persisted for a period of several months until most of the lambs had apparently recovered. However, colonization of the respiratory tract of the lambs by M. ovipneumoniae preceded the production of these antibodies. Sequential serum samples taken from another flock, with no known history of this coughing, showed no such antibodies throughout the sampling period. It is suggested that an immunopathologic mechanism involving production of autoantibodies directed against a ciliary antigen of the lambs could be a contributing factor to the pathogenesis of this clinical disease.

A gene probe to detect Mycoplasma hyopneumoniae, the etiological agent of enzootic porcine pneumonia

Enzootic porcine pneumonia is caused by Mycoplasma hyopneumoniae. Since the disease is of world-wide importance it is important to detect and identify the causative agent. In experience laboratories this mycoplasma can usually be detected by culture but its identification still is difficult and time consuming. We have cloned random Eco R1 fragments of M. hyopneumoniae DNA to M13mp19 and used the resultant recombinant to produce a probe capable of detecting approximately 10 pg of the mycoplasma DNA (10(4) organisms). By using appropriate stringency the test was made specific for M. hyopneumoniae, although at lower stringency reaction was positive with Mycoplasma flocculare at 1000 x the concentration limit. The assay did not detect M. hyopneumoniae in DNA from lungs of chronically infected animals but it did react with DNA isolated from the organisms cultured from the infected lung material.

Stimulation of immunoglobulin-containing cells and isotype-specific antibody response in experimental Mycoplasma hyopneumoniae infection in specific-pathogen-free pigs

The development of immunoglobulin-containing cells and antigen-specific plasma cells in retropharyngeal and bronchial lymph nodes, in lung tissue, and in nasal mucous membrane was followed during an experimental infection of pigs with Mycoplasma hyopneumoniae. An enzyme-linked immunosorbent assay was used to follow stimulation of the immunoglobulin isotypes (classes) M, G, and A directed against the infectious agent in tracheobronchial secretions and systemically. A significant increase of antigen-specific plasma cells in lymph nodes and lung tissue as well as antibodies in tracheobronchial secretions was demonstrated 2 weeks after infection. This specific reaction was followed by a marked increase of immunoglobulin-containing cells in lymph nodes and lung tissue. The data are discussed in terms of autoimmune reactions in the pathogenesis of enzootic pneumonia.