EOSINOPHILIA AND INTRACRANIAL WORM RECOVERY IN INTERLEUKIN-5 TRANSGENIC AND INTERLEUKIN-5 RECEPTOR-ALPHA CHAIN-KNOCKOUT MICE INFECTED WITH ANGIOSTRONGYLUS-CANTONENSIS

We infected interleukin-5 (IL-5)-transgenic (IL-5-Tg) and IL-5 recepto r alpha knockout (IL-5R alpha(-/-)) mice with Angiostrongylus cantonen sis to determine the possible roles of IL-5 and eosinophils in A. cant onensis infection in mice. IL-5-Tg mice demonstrated significantly hig her eosinophilia in bone marrow, blood and cerebrospinal fluid (CSF), lower intracranial worm recovery and smaller female worms than naive C 3H/HeN mice. Both IL-5-Tg and C3H/HeN mice evoked antigen-specific ser um and CSF IgA antibody responses as early as days 5 and 7 postinfecti on, respectively. Prominent eosinophil infiltration was noted around i ntracranial worms in the subarachnoid spaces of the mouse brains; eosi nophils adhering to the worm surface were degranulated. In contrast, I L-5R alpha(-/-) mice yielded a higher worm recovery than wild-type or heterozygous mice at day 20 postinfection and failed to provoke CSF eo sinophilia. These findings indicate that A. cantonensis infection in t he mouse causes IL-5 production and subsequent CSF eosinophilia, the l atter probably being involved in the killing of intracranial worms.