Schistosoma mansoni: evidence that 'non-permissiveness' in 129/Ola mice involves worm relocation and attrition in the lungs.
129/Ola mice resemble WEHI 129J mice in that around 70% of the individuals in any given population resist a primary infection with Schistosoma mansoni. Squashed-organ autoradiographic tracking of [75Se]selenomethionine-labelled parasites has shown that the kinetics of worm migration in 129/Ola mice follows the expected pattern, and that all rodents harbour essentially similar numbers of worms on day 14 post-infection. Combined lung and liver worm recovery techniques have revealed, however, that segregation of mice into 'permissive' and 'non-permissive' individuals can first be detected on day 20. 'Non-permissive' mice are characterized by the absence of schistosome eggs at all times in the liver parenchyma and, in consequence, lack the attendant manifestations of pathology; they do, however, harbour a few stunted worms in the liver and significant numbers of adult schistosomes in the pulmonary vasculature. Histological analysis of sectioned lung tissue from such animals indicates that some lung-located schistosomes feed, pair and lay eggs. Nevertheless, eosinophil-enriched inflammatory reactions develop around such worms and the parasites themselves exhibit various manifestations of trauma, ranging from minor vacuolation to gut herniation and extrusion. The phenomenon of 'non-permissiveness' thus involves retardation of worm development in the liver and, in consequence, relocation of the parasites to the lungs, where they become subject to host effector responses.
Elsaghier
A A
AA
National Institute for Medical Research, Mill Hill, London, UK.
Knopf
P M
PM
Mitchell
G F
GF
McLaren
D J
DJ
D000818:Animals; D008099:Liver / Q000469:parasitology; D008168:Lung / Q000469:parasitology* / Q000473:pathology; D051379:Mice; D008815:Mice, Inbred Strains; D009068:Movement; D012550:Schistosoma mansoni / Q000502:physiology; D012555:Schistosomiasis mansoni / Q000276:immunology* / Q000469:parasitology / Q000473:pathology; D013997:Time Factors