Further protection studies using recombinant forms of Haemonchus contortus cysteine proteinases.
Significant levels of protection against Haemonchus contortus have been achieved in sheep by vaccination with a cysteine proteinase-enriched fraction (TSBP) isolated from the gut of adult parasites. Protection is associated with three cathepsin B-like cysteine proteinases (hmcp 1, 4 & 6). Lambs vaccinated with these proteinases, expressed in bacteria as glutathione S-transferase fusion proteins, had significantly reduced (38%) worm burdens compared to challenge controls although, intriguingly, egg output was unaffected. Here, a repeat trial with similar results is reported and protection obtained compared to that induced by vaccination with the predicted mature forms of hmcp1, 4 and 6 expressed in bacteria as non-fusion proteins. Sheep immunized with a cocktail of these non-fusion proteins had reduced faecal egg counts of 27% (P = 0.17) and worm burdens of 29% (P = 0.01) compared to controls. High levels of host serum IgG were detected in GST-hmcp and non-fusion hmcp-immunized animals, although no correlation with protection could be determined. Sera from these groups bound to the microvillar surface of the gut of H. contortus.
Redmond
D L
DL
Moredun Research Institute, International Research Centre, Pentlands Science Park, Penicuik, Midlothian, UK. redmd@mri.sari.ac.uk
Knox
D P
DP
D000018:Abomasum / Q000469:parasitology; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D015153:Blotting, Western / Q000662:veterinary; D003546:Cysteine Endopeptidases / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005243:Feces / Q000469:parasitology; D005260:Female; D005767:Gastrointestinal Diseases / Q000276:immunology / Q000469:parasitology / Q000517:prevention & control / Q000662:veterinary*; D006188:Haemonchiasis / Q000276:immunology / Q000469:parasitology / Q000517:prevention & control / Q000662:veterinary*; D006189:Haemonchus / Q000201:enzymology* / Q000276:immunology*; D008297:Male; D008856:Microscopy, Fluorescence / Q000662:veterinary; D010270:Parasite Egg Count / Q000662:veterinary; D011994:Recombinant Proteins / Q000276:immunology; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology / Q000469:parasitology* / Q000517:prevention & control*
D000909:Antibodies, Helminth; D011994:Recombinant Proteins; D003546:Cysteine Endopeptidases