Immunoprotection Efficacy of Con A-Purified Proteins against Haemonchus contortus in Goats

Abstract

Parasitic nematodes are important pathogens that infect animals, causing significant economic losses globally. Current repeated treatments have led to widespread anthelmintic resistance in nematode populations, so vaccine development offers an alternative control approach. However, only one effective vaccine (named Barbervax) has been developed to protect animals against one of the most pathogenic nematodes of ruminants—Haemonchus contortus (the barber’s pole worm). This vaccine contains a dominant component, Concanavalin A (Con A) purified H11 antigen, which has been shown to induce high levels (>85%) of immune protection in sheep breeds, but in goat breeds, the immunoprotection test of this native protein is still lacking. Here, we evaluated the protective efficacy of low-dose Con A-purified proteins for controlling the H. contortus infection in goats. Four-month-old Boer goats were equally divided into two vaccinated groups of 5 μg and 10 μg native proteins, and one adjuvant control. Each goat was immunized subcutaneously thrice and then challenged with 7000 infective third-stage larvae (L3s). The fecal egg count (FEC), degree of anemia, antibody levels of serum and abomasum mucosa, as well as worm burdens, were detected in experimental goats. Our results showed that both 5 μg and 10 μg vaccinated groups induced the effective protection in goats, reduced mean FEC by 71.8% and 68.6%, and mean worm burdens by 69.8% and 61.6%, respectively, compared to the adjuvant control. In addition, we detected that the serum antibody responses to the Con A-purified proteins were dominated by the IgG subtype, but the mucosal antibody responses were not detected. These data demonstrate Con A-purified proteins induced effective immunoprotection in goats, and underline their significance for controlling this widespread parasite.

A member of the CAP protein superfamily, Hc-CAP-15, is important for the parasitic-stage development of Haemonchus contortus

“…Hc -CAP-15 was also detected in the intestinal cytoplasm of female adults and intestinal microvillus of male adults, indicating that its possible functions in blood-sucking nematodes are more complex than those of free-living nematodes, such as absorbing nutrients and regulating development. Moreover, many antigens distributed in the intestines are promising candidates for effective vaccines [ 48 – 51 ]. Interestingly, in adult H. contortus , Hc -CAP-15 was not observed in the male reproductive organs, but it was found to be abundant in the oocytes of ovaries in the female, suggesting that this protein is integral to egg production and/or pre-embryonic development and that its function differs significantly between males and females.…”

Anthelmintic activity of Carica pubescens aqueous seed extract and its effects on rumen fermentation and methane reduction in Indonesian thin-tailed sheep: An in vitro study

“…Parasitic nematodes are important pathogens that infect animals and cause significant economic losses worldwide. Haemonchus contortus (barber pole worm) is one of the most pathogenic nematodes of ruminants [ 1 ]. Gastrointestinal nematodes (GINs) are important pathogens of small ruminants that cause significant losses to these livestock species [ 2 ].…”