Immunization with an affinity purified protein extract from the adult parasite protects lambs against infection with Haemonchus contortus.
Young lambs were immunized with membrane protein extracts from adult Haemonchus contortus which had been enriched for cysteine protease activity using Thiol-Sepharose chromatography. The resulting extract comprised several peptides including cysteine as well as serine and metallo-protease activities although the former predominated. A limited number of the peptide components were glycosylated. Following a single challenge infection with the same parasite, vaccinated lambs had substantially reduced faecal egg outputs and final worm burdens (overall means of 77% and 47%, respectively, from three trials) compared with challenge controls. Antibody in sera from vaccinated lambs was almost exclusively bound to the surface of the parasite gut indicating that protection may be mediated by the inhibition of parasite digestion.
D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D002846:Chromatography, Affinity; D003429:Cross Reactions; D003546:Cysteine Endopeptidases / Q000302:isolation & purification / Q000627:therapeutic use; D005260:Female; D006023:Glycoproteins / Q000378:metabolism; D006188:Haemonchiasis / Q000517:prevention & control / Q000662:veterinary*; D006189:Haemonchus / Q000201:enzymology; D015801:Helminth Proteins / Q000302:isolation & purification / Q000627:therapeutic use*; D007422:Intestines / Q000201:enzymology; D037102:Lectins / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000627:therapeutic use; D010455:Peptides / Q000032:analysis; D012756:Sheep; D012757:Sheep Diseases / Q000517:prevention & control*; D014611:Vaccination