It was shown that vaccination with recombinant TsSP induced a Th2 immune response and production of anti-rTsSP antibodies that confer partial protection against challenge infection (Liu et al., 2015[36]), while recombinant serine protease from T. spiralis adults provoked a mixed Th1/Th2 response with elevated production of IFN-γ, IL-4 and IL-10 (Xu et al., 2021[62]). This evidence concerns the gene IL4 and infection.