Experimental schistosomiasis, protective aspects of granulomatous reaction in the mouse liver.
We show two mechanisms of liver protection by the granulomatous reaction against Schistosoma mansoni eggs entrapped in the organ. First, eosinophil peroxidase and its substrate H(2)O(2) are released by inflammatory cells in the immediate vicinity of the parasite eggs. The efficiency of this process was demonstrated by administration of antioxidants to infected mice. The treatment, which reduces H(2)O(2) production, significantly improved the ability of parasite eggs to hatch after collection from the liver. Secondly, we labeled the released egg antigens in liver histological sections and we found that the lattice of collagen fibers which is built around eggs appears to create a barrier preventing released compounds from diffusing freely in surrounding tissues. Together, oxidative processes and antigen containment allow the parasitized liver to cope with the dual threat posed by parasite eggs, i.e. a highly resistant chitinous eggshell and the release of toxic substances.
Hanna
Stéphane
S
INSERM U399, IFR 48, Univ. Mediterranee, 27 Blvd J-Moulin, 13005 Marseille, France.
Gharib
Bouchra
B
Lepidi
Hubert
H
Montet
Jean-Claude
JC
Dumon
Henri
H
de Reggi
Max
M
D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology / Q000378:metabolism; D000975:Antioxidants / Q000494:pharmacology; D006224:Cricetinae; D047209:Eosinophil Peroxidase / Q000378:metabolism; D005260:Female; D015745:Granuloma, Foreign-Body / Q000276:immunology* / Q000469:parasitology; D006861:Hydrogen Peroxide / Q000378:metabolism; D008099:Liver / Q000276:immunology* / Q000469:parasitology; D008109:Liver Diseases, Parasitic / Q000276:immunology* / Q000469:parasitology / Q000517:prevention & control; D008297:Male; D008647:Mesocricetus; D051379:Mice; D008808:Mice, Inbred CBA; D010270:Parasite Egg Count; D051381:Rats; D017207:Rats, Sprague-Dawley; D012550:Schistosoma mansoni / Q000187:drug effects / Q000254:growth & development / Q000472:pathogenicity*; D012555:Schistosomiasis mansoni / Q000276:immunology* / Q000469:parasitology / Q000517:prevention & control
D000947:Antigens, Helminth; D000975:Antioxidants; D006861:Hydrogen Peroxide; D047209:Eosinophil Peroxidase