As shown in Table 3 the positive rates of Sj23HD specific IgM and IgG on day 21 post-infection were 40% and 20% in mice infected with 5 cercariae (group B); 80% and 60% in mice infected with 10 cercariae (group C); both 80% in mice infected with 15 cercariae (group D); and 100% and 80% in mice infected with 20 cercariae (group E), respectively. Here, CD40LG is linked to infection.