immunoprotection in sheep against haemonchus contortus using its thiol-purified excretory/secretory proteins

excretory/secretory antigen was prepared by culturing live adult worms of haemonchus contortus in rpmi 1640 medium at a concentration of 50 worms per ml in a culture-flask at 37 ˚c for 24 hr and the culture supernatant was used as antigen. the e/s antigen was purified by thiol-sepharose affinity chromatography. on western blot analysis, it was demonstrated that thiol-purified antigen showed a single reactive band at 66 kda. in immunization trial, sheep were administered intramuscularly with 500 μg of thiol-purified excretory/secretory antigen along with montanide as adjuvant on day 0, 30 and 60. on elisa, it was observed that the mean absorbance values were significantly (p ≤ 0.01) higher up to 20 weeks post immunization in group-i (purified antigen) compared to group- ii (unimmunized control). further, the mean epg values was lower in group i (200.00 ± 40.82 to 400.00 ± 91.29) than group ii (2200.00 ± 108.01 to 5100.00 ± 169.56) and the percentage reduction in mean fecal egg counts was 88.50%. similarly, the mean abomasal worm counts was lower in group i (808.33 ± 78.29) than group ii (3280.00 ± 147.19) and the percentage reduction in mean abomasal worm count was 75.40%.