Characterization of the trehalase function of Haemonchus contortus and its immunomodulatory effect on host PBMCs

Trehalase can hydrolyze trehalose and is the first key enzyme in the chitin synthesis pathway of arthropods. However, little is known about the function of trehalase in Haemonchus contortus (HcTre). In this study, the purified recombinant HcTre protein (rHcTre) was obtained by prokaryotic expression technology, and it was proved that rHcTre protein has trehalase activity. Western blot results verified that HcTre protein belongs to the excretory/secretory proteins of H. contortus, and rHcTre protein can be recognized by goat serum infected with H. contortus. Moreover, Western blot results demonstrated the expression of the HcTre gene in various developmental stages of H. contortus, with the highest level observed during the egg stage. Meanwhile, the immunofluorescence results revealed a widespread distribution of HcTre protein in adult worms. Interestingly, we found that rat serum against rHcTre protein inhibited the development of larvae by blocking the activity of trehalase. Furthermore, the results showed that rHcTre protein significantly inhibited the proliferation and promoted the apoptosis of goat PBMCs in a dose-dependent manner. This study is expected to further understand the immune escape mechanism of H. contortus and provide new drug targets and vaccine candidate molecules for the prevention and control of the disease.