Pulmonary granuloma formation in murine toxocariasis: transfer of granulomatous hypersensitivity using bronchoalveolar lavage cells.

A major drawback to studying granuloma formation in murine toxocariasis is the ability of the second-stage larva of Toxocara canis to escape from a developing granuloma, migrate elsewhere, and initiate granuloma formation anew. In an attempt to circumvent this difficulty, 2 different T. canis-derived antigenic preparations were covalently attached to Sepharose 4B beads and embolized into the microvasculature of the lungs of CBA/J mice that had been infected 10 days previously with 25 T. canis ova. Both T. canis egg extract (TEE) and T. canis exoantigens (TEX) were able to elicit antigen-specific granulomas 6 days postembolization as determined by both histologic and morphologic criteria. Histologically, the eosinophil-rich granulomas forming around antigen-coated beads embolized into infected mice resembled the developing granuloma previously described forming around the second-stage larva. Attempts to transfer granulomatous reactivity in this model using either immune spleen cells or immune serum were unsuccessful. Successful transfer of granulomatous hypersensitivity was achieved using cells obtained by bronchoalveolar lavage of previously infected mice. The results suggest the feasibility of using this embolic model of granuloma formation in murine toxocariasis.