Expulsion of Nippostrongylus brasiliensis from mice lacking antibody production potential

Expulsion of the intestinal nematode of rodents, Nippostrongylus brasiliensis, was assessed in mice experiencing the immunosuppressive effects of anti-micron antibodies. Anti-micron treatment resulted in complete elimination of IgM and severe reduction of IgG1, IgG2 and IgA serum immunoglobulin levels. Specific antibody responses to sheep erythrocytes were virtually eliminated in anti-micron-treated mice as determined by direct and indirect plaque-forming-cell responses, haemagglutination and haemolytic assays. Using passive cutaneous anaphylaxis (PCA) and indirect haemagglutination (IHA) assays, antibodies against N. brasiliensis were not detectable in sera of anti-micron-treated mice; control mice, however, generated strong PCA and IHA responses. The kinetics of worm egg production coupled with adult worm recoveries at necropsy indicate that anti-micron treatment of mice had little or no effect on the capacity of mice to expel N. brasiliensis even though antibody production potential had been eliminated in these mice. Thus, anti-worm antibodies may not be requisite in the mechanism of N. brasiliensis expulsion from mice.