Protection studies of an excretory–secretory protein HcABHD against Haemonchus contortus infection

Abstract

Unlike the successful immunization of native H. contortus antigens that contributed to the realization of the first commercial vaccine Barbervax, not many studies revealed the encouraging protective efficacies of recombinant H. contortus antigens in laboratory trials or under field conditions. In our preliminary study, H. contortus α/β-hydrolase domain protein (HcABHD) was demonstrated to be an immunomodulatory excretory–secretory (ES) protein that interacts with goat T cells. We herein evaluated the protective capacities of two HcABHD preparations, recombinant HcABHD (rHcABHD) antigen and anti-rHcABHD IgG, against H. contortus challenge via active and passive immunization trials, respectively. Parasitological parameter, antibody responses, hematological pathology and cytokine profiling in unchallenged and challenged goats were monitored and determined throughout both trials. Subcutaneous administration of rHcABHD with Freund adjuvants elicited protective immune responses in challenged goats, diminishing cumulative fecal egg counts (FEC) and total worm burden by 54.0% and 74.2%, respectively, whereas passive immunization with anti-rHcABHD IgG conferred substantial protection to challenged goats by generating a 51.5% reduction of cumulative FEC and a 73.8% reduction of total worm burden. Additionally, comparable changes of mucosal IgA levels, circulating IgG levels, hemoglobin levels, and serum interleukin (IL)-4 and IL-17A levels were observed in rHcABHD protein/anti-rHcABHD IgG immunized goats in both trials. Taken together, the recombinant version of HcABHD might have further application under field conditions in protecting goats against H. contortus infection, and the integrated immunological pipeline of ES antigen identification, screening and characterization may provide new clues for further development of recombinant subunit vaccines to control H. contortus.

Haemonchosis in Sheep and Goats, Control Strategies and Development of Vaccines against Haemonchus contortus

“…Because of the immunomodulatory features during parasite-host interaction, rHcABHD was considered a promising vaccine target. Indeed, administration of recombinant HcABHD in goats led to a moderate reduction of FECs [ 69 ]. Another ES antigen, adhesion-regulating molecule 1 (HcADRM1), was expressed in E. coli in its soluble form and tested in goats.…”

Prospects of Using High-Throughput Proteomics to Underpin the Discovery of Animal Host–Nematode Interactions

“…Considerable effort has also gone into identifying and evaluating immunogenic proteins present in the secretome of Haemonchus contortus [ 43 , 44 , 45 ]. Using co-immunoprecipitation, combined with shotgun LC-MS/MS, Lu et al [ 45 ] identified 114 ES proteins that interact with host T cells, including a series of proteases, SCP/TAPS proteins and C-type lectins.…”

“…Using co-immunoprecipitation, combined with shotgun LC-MS/MS, Lu et al [ 45 ] identified 114 ES proteins that interact with host T cells, including a series of proteases, SCP/TAPS proteins and C-type lectins. Thus, this study provided a first insight into the interplay between this parasite ( via ES products) and the immune system ( via effector cells), and also proposed possible vaccine candidates, such as the α/β-hydrolase domain protein (HcABHD), of which a recombinant version has been reported to achieve up to 70% protection against Haemonchus contortus challenge infection in a subsequent study [ 44 ].…”

Immunization With Recombinant Haemonchus contortus Y75B8A.8 Partially Protects Local Crossbred Female Goats From Haemonchus contortus Infection

“…Bu et al demonstrated that rHcftt-2 identified from HcESPs reduced mean eggs per gram in feces (EPG) and worm burdens by 26.46 and 32.33%, respectively ( 16 ). More recently, H. contortus α/β-hydrolase domain protein (HcABHD) was identified as an immunomodulatory antigen that interacts with goat T cells, and it could induce significant reductions in egg shedding (54%) and worm burden (74.2%) ( 17 ). Given the performance of ES antigens for their immunogenicity and performance in recombinant forms, it was meaningful to explore more new ES proteins and their active form in vaccine development.…”