Parasite and egg burden, hepatic collagen and histologic pattern of liver granulomas in selection III high and low antibody responder mice infected with Schistosoma mansoni.

Selection III mice have particular immunological characteristics: they are high (H III) or low (L III) antibody producer animals, yet both lines display similar T cell responses and macrophage activities. We submitted these mice to infection with Schistosoma mansoni to assess in vivo parasite and egg burden, hepatic collagen and cellular composition of granulomas in both lines. Titration of anti-Schistosoma IgG by ELISA showed remarkably higher values in H III line, at both studied periods (8th and 12th weeks post-infection). Nevertheless, the number of adult worms recovered from the portal system was similar in both lines, being not associated with anti-Schistosoma antibody levels. There is an increase in hepatic collagen from the 8th to the 12th weeks post-infection, which is paralleled by an increase in the number of eggs in the liver. This association apparently occurs at the same ratio in H III and L III animals. The most important difference found between the two lines was the outstanding contrast in terms of volume and eosinophil counts in the granulomas, with lesions from H III mice clearly being larger and containing more of these cells than LIII lesions.