Schistosoma mansoni: development of primary infections in mice genetically deficient or intact in the fifth component of complement

Abstract

The influence of the late components of complement (C) on percutaneous primary infections with S. mansoni was studied in inbred mice genetically deficient or intact in C5. Worm recoveries were diminished in C5-deficient male mice as compared to C5-intact animals; 24-day old parasites were shorter following growth in C5-deficient animals. At 7 wk after infection, female schistosomes, but not male parasites, were shorter, and fewer eggs/schistosome pair were deposited in the livers of C5-deficient as compared to C5-intact male mice. In addition to the presence of C5, sex influenced the outcome of an infection. Schistosomes showed a reduced infection rate and were relatively stunted after 24 days of growth in female mice of the 2 strains as compared to male mice of the corresponding strains. Apparently, C5 plays no role in defense against a primary infection in mice.