The Journal of Medical Microbiology, Vol 42, Issue 6 433-441, Copyright © 1995 by Society for General Microbiology
Experimental Legionnaires' disease in SCID-Beige mice reconstituted with human leucocytes
A. Williams, B. W. McBride, G. Hall, R. B. Fitzgeorge and G. H. Farrar
Centre for Applied Microbiology and Research (CAMR), Porton Down, Salisbury, Wiltshire.
A new small animal model of experimental Legionnaires' disease is described
in which the reconstitution of SCID-Beige mice with human peripheral blood
leucocytes permits the in-vivo growth of Legionella pneumophila in the
lungs of aerosol-challenged mice. Following infection, viable bacterial
counts within the lungs of mice increased from 10(5) cfu/lung at the time
of inoculation to a maximum of 10(10) cfu/lung by 48 h post-inoculation.
Two types of disease were detected in the lungs of infected SCID-Beige
mice. An acute exudative bronchiolitis and bronchopneumonia were seen in
the most severely affected mice and, in the less severely affected mice,
lesions of subacute or chronic disease were seen with thickening of
alveolar walls and consolidation of lung tissue. Human cells did not appear
to be involved directly in the pathology but were required for the
establishment of infection. Immunohistological staining of lung tissue
revealed substantial amounts of bacterial antigen distributed in a pattern
similar to that seen in human Legionnaires' disease.
