Copyright © 1997, American Society for Microbiology Infection of BALB/c Mice with the Filarial Nematode

Litomosoides sigmodontis is the only filaria which develops from infective larvae into adults in immunocom-petent laboratory mice. Depletion of CD41 T cells from infected BALB/c mice resulted in worm and microfi-larial burdens significantly higher than those of infected controls. Th2 cytokines, eosinophilia, and immuno-globulin E, which were strongly induced in infected controls, were diminished in CD4-depleted mice. Filariasis is an arthropod-borne parasitism which affects an-imals and humans, debilitating more than 120 million people (26, 27). Infective third-stage larvae (L3 larvae) are injected into the host during a blood meal of the arthropod vector and develop into adult worms which release microfilariae (Mf) into either the skin (e.g., onchocerciasis) or the blood (lymphatic filarioses). None of the murine models in which immunity to filarial infection has been analyzed (1, 2, 5, 13, 21) allows development of L3 larvae into adult worms in immunocompetent inbred animals. Therefore, we made use of the experimental infectio