Identification of excretory and secretory proteins from Haemonchus contortus inducing a Th9 immune response in goats

Systems biology of Haemonchus contortus - Advancing biotechnology for parasitic nematode control

Parasitic nematodes represent a substantial global burden, impacting animal health, agriculture and economies worldwide. Of these worms, Haemonchus contortus - a blood-feeding nematode of ruminants - is a major pathogen and a model for molecular and applied parasitology research. This review synthesises some key advances in understanding the molecular biology, genetic diversity and host-parasite interactions of H. contortus, highlighting its value for comparative studies with the free-living nematode Caenorhabditis elegans. Key themes include recent developments in genomic, transcriptomic and proteomic technologies and resources, which are illuminating critical molecular pathways, including the ubiquitination pathway, protease/protease inhibitor systems and the secretome of H. contortus. Some of these insights are providing a foundation for identifying essential genes and exploring their potential as targets for novel anthelmintics or vaccines, particularly in the face of widespread anthelmintic resistance. Advanced bioinformatic tools, such as machine learning (ML) algorithms and artificial intelligence (AI)-driven protein structure prediction, are enhancing annotation capabilities, facilitating and accelerating analyses of gene functions, and biological pathways and processes. This review also discusses the integration of these tools with cutting-edge single-cell sequencing and spatial transcriptomics to dissect host-parasite interactions at the cellular level. The discussion emphasises the importance of curated databases, improved culture systems and functional genomics platforms to translate molecular discoveries into practical outcomes, such as novel interventions. New research findings and resources not only advance research on H. contortus and related nematodes but may also pave the way for innovative solutions to the global challenges with anthelmintic resistance.

Enhancing H11 Protein-Induced Immune Protection Against Haemonchus contortus in Goats: A Nano-Adjuvant Formulation Strategy

The only vaccine against Haemonchus contortus is limited by short-lived antibody persistence and the need for frequent booster immunizations. This study leveraged the advantages of nano-adjuvants in enhancing antigen presentation and immune regulation to evaluate the efficacy of novel adjuvants (IMX, AddaS03) and the conventional QuilA combined with H11 protein. Goats were divided into four groups (IMX + H11, AddaS03 + H11, QuilA + H11, and infected control). They were immunized three times and challenged with 6000 infective third-stage larvae (iL3s) of H. contortus on the day of the third immunization, with the experiment lasting for 98 days. The results showed that vaccination with IMX + H11 conferred the strongest protection, demonstrating 88.3% efficacy in fecal egg count (FEC) reduction and 75.8% efficacy against worm burden, followed by QuilA + H11 (85.2% FEC reduction and 68% worm burden reduction) and AddaS03 + H11 (79.4% FEC reduction and 61.3% worm burden reduction). Serum IgG analysis revealed high antibody levels in all immunized groups. Cytokine detection found that IMX + H11 significantly upregulated IL-2 and IFN-γ expression in PBMCs and TNF-α expression in splenocytes, activating Th1-type responses and immune memory. QuilA + H11 showed weaker Th1 activation, and AddaS03 + H11 faced limitations due to insufficient antibody persistence for long-term protection. These findings suggest that IMX can induce highly efficient humoral and cellular immunity, providing a new direction for the optimization of H. contortus vaccines and suggesting the importance of nano-adjuvants for precise regulation of immune patterns.

Characterization of the trehalase function of Haemonchus contortus and its immunomodulatory effect on host PBMCs

Trehalase can hydrolyze trehalose and is the first key enzyme in the chitin synthesis pathway of arthropods. However, little is known about the function of trehalase in Haemonchus contortus (HcTre). In this study, the purified recombinant HcTre protein (rHcTre) was obtained by prokaryotic expression technology, and it was proved that rHcTre protein has trehalase activity. Western blot results verified that HcTre protein belongs to the excretory/secretory proteins of H. contortus, and rHcTre protein can be recognized by goat serum infected with H. contortus. Moreover, Western blot results demonstrated the expression of the HcTre gene in various developmental stages of H. contortus, with the highest level observed during the egg stage. Meanwhile, the immunofluorescence results revealed a widespread distribution of HcTre protein in adult worms. Interestingly, we found that rat serum against rHcTre protein inhibited the development of larvae by blocking the activity of trehalase. Furthermore, the results showed that rHcTre protein significantly inhibited the proliferation and promoted the apoptosis of goat PBMCs in a dose-dependent manner. This study is expected to further understand the immune escape mechanism of H. contortus and provide new drug targets and vaccine candidate molecules for the prevention and control of the disease.

In vitro culture of the parasitic stage larvae of hematophagous parasitic nematode Haemonchus contortus

Current research on common parasitic nematodes is limited because their infective stages cannot be propagated in vitro. Here, we report a culture system for developing L4s of Haemonchus contortus, a blood-feeding nematode of ruminants. Our results demonstrated that a proportionate mixture of NCTC-109 to Luria-Bertini (1:2) media promoted the formation of early L4s and then into late L4s upon inclusion of 12.5% (v/v) defibrinated blood, albeit with a decline in survival. Adding antioxidants (0.3 mg/mL of L-glutathione or 200 nmol of vitamin C) improved survival of L4s, with approximately 90% developing to late L4s by 22 days. These L4s showed parallel morphological features (such as digestive and reproduction systems) compared with in vivo L4s at day 7 (following challenge infection), although with delayed development. Our work optimized the in vitro culture system for L4s while providing an important platform for in-depth molecular research on Haemonchus and other related parasitic nematodes.

Effects of immune response on different nano-adjuvants combined with H11 antigen of Haemonchus contortus

The intestinal native protein H11 is one of the most immunodominant antigen of Haemonchus contortus. However, H11 combined with QuilA adjuvant shows only short-lived protection for animals. Nano-adjuvants have the huge potential to extend the immune response in human and animals. Here, we compared the immune responses induced by H11 combined with three nano-adjuvants including lipid nanoparticles (LNP), immunostimulating complex matrix (IMX) and AddaS03™. We measured the cytokine levels of goat PBMCs stimulated by H11 mixed with three nano-adjuvants and QuilA. Results showed that the transcriptions of IL-6, IL-8 and IFN-γ genes were significantly inhibited in all adjuvant group compared with PBS control. H11-IMX combination significantly up-regulated IL-2, IL-17 and TNF-α gene transcriptions. The H11-LNP group showed a significant increase in IL-17 and TNF-α transcriptions, while the H11-AddaS03™ group significantly increased IL-2 transcription. Additionally, mice immunized with these formulations were assessed for splenic lymphocyte proliferation. All H11-adjuvant combinations, except H11-LNP, significantly stimulated lymphocyte proliferation compared to the H11 alone and PBS control groups, with the H11-AddaS03™ combination showing the strongest effect. Analysis of serum antibody levels revealed that all immune groups induced high IgM levels, with H11-IMX inducing the highest IgG levels. Our results demonstrated that IMX or LNP combined with H11 mainly induced a Th17 cell immune response in goat PBMCs, while IMX or AddaS03™ combined with H11 could induce a strong humoral immune response in mice. This study elucidates the immune response profiles of different nano-adjuvant combined with H11 antigen, providing important insights for vaccine development against parasitic nematodes.

A Comprehensive Review on Haemonchus contortus Excretory and Secretory Proteins (HcESPs): TH-9 stimulated ESPs as a potential candidate for Vaccine Development and Diagnostic Antigen

Haemonchus contortus (Barber pole worm) is one of the dominant helminth parasitic infections in small ruminants which is economically important and causes severe losses in the livestock industry, particularly in tropical and subtropical regions. This parasite resides in the abomasum and is responsible for severe blood loss, leading to anemia, emaciation, hypoproteinemia, weight loss, and potentially death. The economic impact of H. contortus on the livestock industry necessitates effective control measures, including early diagnosis and the development of effective vaccines. H. contortus secretes a variety of excretory and secretory proteins (ESPs), which are glycoproteins that play a crucial role in modulating the host's immune response. These ESPs are not only vital for understanding the immunological interactions between the parasite and the host but also serve as potential diagnostic tools and vaccine candidates. Similar ESPs have been identified in other parasitic species such as Cooperia spp, Ostertagia ostertagia, Teladorsagia circumcincta, Ascaris sum, Schistosoma japonicum, and Echinococcus multilocularis, underscoring their importance in both detection and vaccine development. In addition, there is a lack of highly potential specific proteins which having immunogenic properties that can be used for the accurate, early diagnosis serologically and serve as a potential candidate for the vaccine development against H. contortus. Recent research highlights that TH-9 stimulated proteins from H. contortus are emerging as promising candidates for vaccine development due to their immunomodulatory effects. These proteins have been shown to induce a TH-9 immune response, characterized by increased production of interleukin-9 (IL-9), which is critical for enhancing protective immunity against helminth infections. It is suggested to investigate TH-9 stimulated protein as potential candidates for vaccine development and diagnostic antigen.

Quantitative proteomics reveals significant variation in host responses of cattle with differing buffalo fly susceptibility

Background

Control of buffalo flies (Haematobia irritans exigua, BFs) relies mainly on chemical methods; however, resistance to insecticides is widespread in BF populations. Breeding for resistance to BFs represents a possible alternative, but direct phenotyping of animals is laborious and often inaccurate. The availability of reliable diagnostic biomarker(s) to identify low BF carrier cattle would facilitate rapid and accurate selection for genetic improvement. However, limited information is available regarding differences amongst cattle in host responses to BF infestation.

Methods

This study investigated the variation in Brangus cattle serum proteomic profiles before (naïve) and after peak BF exposure, in low (LF) and high BF burden (HF) cattle. Cattle were phenotyped for susceptibility based on BF counts on multiple dates using visual and photographic techniques. The relative abundance of serum proteins in cattle before and after exposure to BFs was analysed using sequential window acquisition of all theoretical fragment ion mass spectrometry (SWATH-MS).

Results

Exposure to BFs elicited similar responses in HF and LF cattle, with 79 and 70 proteins, respectively, showing significantly different abundances post exposure as compared to their relevant naïve groups. The comparison of serum samples from naïve HF and LF cattle identified 44 significantly differentially abundant (DA) proteins, while 37 significantly DA proteins were identified from the comparison between HF and LF cattle post-exposure to BFs. Proteins with higher abundance in naïve LF cattle were enriched in blood coagulation mechanisms that were sustained after exposure to BFs. Strong immune response mechanisms were also identified in naïve LF cattle, whereas these responses developed in HF cattle only after exposure to BF. High BF cattle also showed active anticoagulation mechanisms in response to BF exposure, including downregulation of coagulation factor IX and upregulation of antithrombin-III, which might facilitate BF feeding.

Conclusion

Underlying differences in the abundance of proteins related to blood coagulation and immune response pathways could potentially provide indirect indicators of susceptibility to BF infestation and biomarkers for selecting more BF-resistant cattle.

Epidemiology and phylogeny of Haemonchus contortus through internal transcribed spacer 2 gene in small ruminants

Introduction

Haemonchus contortus (H. contortus) is a blood-feeding nematode causing infectious disease haemonchosis in small ruminants of tropical and subtropical regions around the world. This study aimed to explore the prevalence and phylogeny of H. contortus in small ruminants using the internal transcribed spacer-2 (ITS-2) gene. In addition, a comprehensive review of the available literature on the status of H. contortus in Pakistan was conducted.

Methods

Fecal samples were collected from sheep and goats (n = 180). Microscopically positive samples were subjected to DNA extraction followed by PCR using species-specific primers.

Results

The overall prevalence of H. contortus was 25.55% in small ruminants. The prevalence of H. contortus was significantly associated with months and area. The highest occurrence of haemonchosis was documented in July (38.70%), whereas the lowest occurred in December (11.11%), with significant difference. The prevalence was highest in the Ghamkol camp (29.4%) and lowest in the arid zone of the Small Ruminant Research Institute (17.5%) (p = 0.01). The results of the systematic review revealed the highest prevalence of haemonchosis (34.4%) in Khyber Pakhtunkhwa (p = 0.001).

Discussion

Phylogenetic analysis revealed a close relationship between H. contortus and isolates from Asia (China, India, Iran, Bangladesh, Malaysia, and Mongolia) and European countries (Italy and the United Kingdom). It has been concluded that H. contortus is prevalent in small ruminants of Kohat district and all over Pakistan, which could be a potential threat to food-producing animals, farmers, dairy, and the meat industry. Phylogenetic analysis indicates that H. contortus isolates share close phylogenetic relationships with species from Asia and Europe.

Haemonchus contortus HcL6 promoted the Th9 immune response in goat PBMCs by activating the STAT6/PU.1/NF-κB pathway

Th9 cells play a crucial role in parasite immunity. The development of Th9 cells is facilitated by several cytokines. Key transcription factors, such as STAT6, STAT5, and PU.1, are known to enhance IL-9 expression during the Th9 immune response. NF-κB-mediated transduction pathways participate in the induction of IL-9. In a previous study, we unveiled a unique ribosomal protein derived from Haemonchus contortus excretory-secretory proteins (HcESPs) that interact with host Th9 cells. In the present study, the effects of the Haemonchus contortus ribosomal protein L6 domain DE-containing protein (HcL6) on IL-9 secretion, Th9 differentiation, and IL-9 transcription were assessed by employing ELISA, flow cytometry, and qPCR methodologies. The observations revealed the transcriptional upregulation of several key genes within the Th9 immune response pathway. Moreover, silencing STAT6, PU.1, and NF-κB was found to attenuate the Th9 immune response. In this study, we unveiled the Th9 immune response-inducing capabilities of HcL6 and elucidated some of its underlying mechanisms. These findings suggest that HcL6 is an immunostimulatory antigen capable of inducing the Th9 immune response. These insights could prove instrumental in identifying potential candidate antigens for the development of immunoprophylactic strategies against H. contortus infections.

Comparative proteomics analysis of adult Haemonchus contortus isolates from Ovis ammon

Haemonchus contortus is an important parasite that causes disease that seriously endangers ruminant animals cattle, sheep, goat, and camel. Here, we compared the proeomics analysis of three adult Haemonchus contortus isolates from mouflons (Ovis ammon). A total of 1,299 adult worm proteins were identified, and 461 proteins were quantified, of which 82 (108), 83 (97), and 97 (86) significantly upregulated (downregulated) differentially expressed proteins (DEPs) were detected among pairwise comparisons (1-vs.-3, 2-vs.-3, and 2-vs.-1). Liquid chromatography–tandem mass spectrometry (LC−MS/MS) and bioinformatic analysis indicated that these DEPs are mainly concentrated in cellular composition, molecular function, biological function, and catabolism pathways. In addition, Gene Ontology (GO) classification and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were carried out to screen the DEPs. The main biological processes involved were nucleotide, nucleotide phosphate, ribonucleotide, purine-containing compound, purine ribonucleotide, single-organism, oxoacid, organic, carboxylic, oxoacid metabolic processes and single-organism catabolic processes. The majority of KEGG pathways were found to be related to metabolic pathways, biosynthesis of secondary metabolites, biosynthesis of antibiotics, carbon metabolism, and microbial metabolism in diverse environments. Moreover, we also found differences in the expression of some important or novel regulatory proteases, such as serine hydroxymethyl transferase (SHMT), dihydrolipoyl dehydrogenase (DLD), and transket pyr domain-containing protein (TKPD). In summary, label-free proteomic analysis of adult H. contortus worms displayed significant differences in three different individual isolates, which helps to improve our understanding of the growth and metabolic mechanisms of H. contortus in different individuals and relative natural environments and provides novel drug targets for the treatment of parasitic diseases.