Vaccination against the nematode Haemonchus contortus with a thiol-binding fraction from the excretory/secretory products (ES)

Abstract

Fractionated excretory/secretory products (ES) of adult Haemonchus contortus were evaluated as protective antigens. The proteins were successively eluted from a Thiol Sepharose column using 25 mM cysteine followed by 25 mM Dl-dithiothreitol (DTT). Sheep were vaccinated three times and challenged with 5000 third stage infective larvae (L3) of H. contortus. Highest level of protection was found in sheep vaccinated with the DTT-eluted fraction in which egg output and worm burden were reduced by 52 and 50%, respectively, compared to the adjuvant control group. There was a positive correlation between fecundity (number of eggs per female) and the cumulative EPG or worm burden. Serum and mucus antibody levels of ES-specific immunoglobulins increased after immunizations and after challenge for IgG, IgA and IgE. The harvesting of H. contortus from animals clustered per group revealed the presence of cysteine protease activity in the ES of all groups but in addition to that, metalloprotease activity was also detected in the groups vaccinated with the DTT-eluted fraction, total ES and adjuvant only, in contrast to previous batches of ES (completely inhibited by E64) obtained from non vaccinated animals.

A Multi-enzyme Cascade of Hemoglobin Proteolysis in the Intestine of Blood-feeding Hookworms

“…Haemonchus galactose-containing glycoprotein is a protein complex from the intestine of the sheep barber's pole worm, H. contortus. Vaccination of sheep with H-gal-GP confers high levels of protection against parasite challenge; the complex is predominantly made up of aspartic, cysteine, and metalloproteases (57), and recent evidence suggests that the purified enzymes from Haemonchus galactose-containing glycoprotein are responsible for the vaccine efficacy (44,58,59). We recently described the efficacy of Ac-CP-2 as an anti-hookworm vaccine in dogs experimentally challenged with A. caninum (21).…”

Immunoprotection in goats against Haemonchus contortus after immunization with cysteine protease enriched protein fractions

“…Cysteine proteases, because of their apparent critical function in worm nutrition, immune evasion or both [21] have also been assessed as vaccine candidates. Cysteine proteases have been implicated in the protection conferred by vaccination with affinity purified detergent-soluble extracts of H. contortus [1,14].…”

ANTIGENIC AND IMMUNOGENIC COMPONENTS OF <i>HAEMONCHUS LONGISTIPES</i> IDENTIFIED BY WESTERN IMMUNOBLOTING

“…In addition the three antigens released during infection may represent excretory-secretory antigens and are expected to be less than those released by physical disruption since the latter contains both somatic and excretorysecretory components. Excretory-secretory antigens of similar molecular weights were reported in H. contortus (Joshi and Singh, 1999;Bakker et al, 2004;Prasad et al, 2008) and in other helminth parasites (Savigny, 1975;Ishiyama et al, 2009;Schnyder et al, 2011). Moreover, the use of rabbit anti-camel serum as a secondary antibody in the immunoblotting test, due to the lack of anti-camel conjugate, before the addition of anti-rabbit conjugate may also contributes to the low number of antigenic components through increasing the possibility of dissociation of antibody bonds during washing cycles.…”