IFNAR1 and infection: IFNAR1−/− mice did not share the heightened parasite immunity phenotype shown by MyD88−/− mice, as similar numbers of adult worms were recovered 28 d post infection as in wild-type C57BL/6 mice (Fig. 7A), and H. polygyrus egg production was even greater in IFNAR1−/− mice than in wild-type controls 28 d following infection (Fig. 7B).