Oral immunotherapy using antibodies against a parasite antigen reduced Haemonchus contortus worm growth, eggs, and inflammatory signs in experimentally infected lambs.
Researchers developed an oral immunotherapy based on antibodies that target ES24, a specific antigen from Haemonchus contortus, a nematode parasite that causes haemonchosis in sheep. They produced purified antibodies from immunized sheep donors and pooled them before testing their effects.
In lab tests, the antibody mix reduced larval infectivity. In lambs given an experimental infection, the treatment lowered worm development and fecundity and reduced inflammatory responses in the abomasum, while also changing measures of immune activity both locally in the gut tissue and in the blood.
Observed effects in lambs
The study produced purified, biologically active antibody immunoglobulins against the ES24 antigen and confirmed antibody levels by ELISA. The antibody mix reduced larval infectivity in vitro. In vivo, lambs receiving the immunotherapy had reduced worm development and fecundity after artificial H. contortus infection, along with lower inflammatory responses, including fewer peripheral monocytes and reduced neutrophil infiltration in the abomasal lamina propria compared with untreated infected lambs. The treatment was also associated with increased expression of TLR4 and GAL11 locally in the abomasum and with lymphocytosis in the blood, especially in female lambs.
