Muscle Larvae Research Articles

Excretory/secretory antigens from Trichinella spiralis muscle larvae ameliorate HFD-induced non-alcoholic steatohepatitis via driving macrophage anti-inflammatory activity

No approved effective therapy for non-alcoholic steatohepatitis (NASH) is currently available. Trichinella spiralis (T. spiralis) infection and their products have positive impact on several metabolic diseases. Considering, we firstly investigated the effects of the T. spiralis-derived Excretory-Secretory antigens (ESA) on high fat diet (HFD)-induced NASH mouse models. To further elucidate the mechanism of action, HepG2 cells were incubated with palmitic acid (PA) to construct NASH-like cell model, and then the culture medium supernatant collected from ESA-treated macrophages was applied to intervene the cell model in vitro. In NASH mouse models, ESA significantly alleviated hepatic steatosis and hepatic inflammation, as reflected by reducing pro-inflammatory cytokines and inactivating TLR4/MYD88/NF-κB pathway and NLRP3 inflammasome. Meanwhile, the HFD-induced oxidative stress was restored by ESA through lessening the level of MDA, increasing the activity of T-SOD and enhancing Nrf2 signaling-related proteins, including p-Nrf2, NQO1, HO-1, GPX4, and p-AMPK. Notably, ESA preferentially promoted macrophages polarization toward M2 anti-inflammatory phenotype in vivo and vitro. Moreover, in vitro, intervention of PA-treated HepG2 cells with medium supernatant of ESA-treated macrophages attenuated lipid accumulation, inflammation, as well as oxidative stress. In conclusion, T. spiralis-derived ESA may serve as a novel promising candidate for the treatment of NASH via its properties of driving macrophage anti-inflammatory activity.

Early diagnosis of Trichinella spiralis and Trichinella nativa: Expression of the serine protease gene at the invasive intestinal and muscular larva stages.

Diagnosis of trichinellosis at the intestinal stage during larval development is the primary challenge in the early detection and treatment of trichinellosis. The use of serine protease as a diagnostic marker for serological tests has been the subject of various studies, but data on Trichinella nativa serine protease in the intestinal phase are still insufficient for a proper diagnosis. This study aimed to establish the duration of the intestinal phase for early diagnosis and to determine the level of expression of the serine protease gene in T. nativa and Trichinella spiralis larvae. We used European isolates from T. spiralis pigs and T. nativa larvae isolated from spontaneously infected wild carnivorous animals (wolf, Karaganda region) in Central Kazakhstan. Isolation of larvae from the meat of infected animals was carried out using the compressor method. For two species of Trichinella, 36 mice (in each group 18 mice) were infected with 250 larvae and euthanized by intramuscular injection of xylazine followed by an intravenous overdose of anestofol at 3, 5, 7, 14, 21, and 30 dpi (each day 3 infected mice) and one control group (3 mice). Sequencing and bioinformatics methods were used to determine the DNA and cDNA of the serine protease gene, and molecular methods (DNA extraction, reverse transcription polymerase chain reaction, and sequence) were used to measure the accumulation of serine protease transcripts in isolated larvae. The results showed differences in the duration of intestinal phase between T. spiralis and T. nativa. The intestinal larvae of T. nativa were observed from 7 to 30 dpi, and the intensity of invasion increased up to 30 dpi (p < 0.001), while in the case of T. spiralis, the increase in larval growth in the intestinal phase decreased to 21 dpi, and only an increase of 1.6 ± 0.88 (p < 0.01) was detected at 30 dpi. T. nativa muscle larvae were detected at 21 dpi, compared with T. spiralis at 14 dpi. This characteristic was also reflected in the levels of serine protease transcripts in the samples. Accumulation was observed in both cases higher in the muscular stage of development, whereas the duration of the intestinal stage of T. nativa made it possible to detect serine protease at 30 dpi. The intestinal stage of T. nativa lasts for 30 days, indicating that the use of T. nativa serine protease is useful for the identification of intestinal infection. Furthermore, this protein can be used to identify T. spiralis and T. nativa in laboratory samples. Serine protease can be used as a marker for serological diagnosis. Within the framework of the research topic, it is important to conduct further studies on the species specificity of the obtained recombinant protein. It is necessary to focus on identifying highly specific Trichinella proteins for early disease detection.

Plancitoxin-1 mediates extracellular trap evasion by the parasitic helminth Trichinella spiralis

BackgroundTrichinella spiralis (T. spiralis) is a parasitic helminth that causes a globally prevalent neglected zoonotic disease, and worms at different developmental stages (muscle larvae, adult worms, newborn larvae) induce immune attack at different infection sites, causing serious harm to host health. Several innate immune cells release extracellular traps (ETs) to entrap and kill most pathogens that invade the body. In response, some unicellular pathogens have evolved a strategy to escape capture by ETs through the secretion of nucleases, but few related studies have investigated multicellular helminths.ResultsIn the present study, we observed that ETs from neutrophils capture adult worms of T. spiralis, while ETs from macrophages trap muscle larvae and newborn larvae, and ETs had a killing effect on parasites in vitro. To defend against this immune attack, T. spiralis secretes plancitoxin-1, a DNase II-like protein, to degrade ETs and escape capture, which is essential for the survival of T. spiralis in the host.ConclusionsIn summary, these findings demonstrate that T. spiralis escapes ET-mediated capture by secreting deoxyribonuclease as a potential conserved immune evasion mechanism, and plancitoxin-1 could be used as a potential vaccine candidate.

Enhanced Genomic and Transcriptomic Resources for Trichinella pseudospiralis and T. spiralis to Underpin the Discovery of Molecular Differences between Stages and Species.

Nematodes of the genus Trichinella are important pathogens of humans and animals. This study aimed to enhance the genomic and transcriptomic resources for T. pseudospiralis (non-encapsulated phenotype) and T. spiralis (encapsulated phenotype) and to explore transcriptional profiles. First, we improved the assemblies of the genomes of T. pseudospiralis (code ISS13) and T. spiralis (code ISS534), achieving genome sizes of 56.6 Mb (320 scaffolds, and an N50 of 1.02 Mb) and 63.5 Mb (568 scaffolds, and an N50 value of 0.44 Mb), respectively. Then, for each species, we produced RNA sequence data for three key developmental stages (first-stage muscle larvae [L1s], adults, and newborn larvae [NBLs]; three replicates for each stage), analysed differential transcription between stages, and explored enriched pathways and processes between species. Stage-specific upregulation was linked to cellular processes, metabolism, and host-parasite interactions, and pathway enrichment analysis showed distinctive biological processes and cellular localisations between species. Indeed, the secreted molecules calmodulin, calreticulin, and calsyntenin-with possible roles in modulating host immune responses and facilitating parasite survival-were unique to T. pseudospiralis and not detected in T. spiralis. These insights into the molecular mechanisms of Trichinella-host interactions might offer possible avenues for developing new interventions against trichinellosis.

The effect of β-Glucan induced intestinal trained immunity against Trichinella spiralis infection

Parasitic helminth Trichinella spiralis (Ts) induce mixed Th1/Th2 response with predominant type 2 immune responses, with protective immunity mediated by interleukin (IL)-4, IL-5, and IL-13. β-Glucan (BG) has been shown to have the ability to induce trained immunity, confers non-specific protection from secondary infections. However, whether BG-induced trained immunity played a role in protective type 2 immunity against Ts infection is unclear. In this study, BG was administered five days before Ts infection to induce trained immunity. Our findings demonstrate that BG pretreatment effectively reduced the number of T. spiralis adults and muscle larvae, whereas inhibition of trained immunity abolished the effect of BG. Additionally, we observed a significant increase in goblet cells and mucus production as evidenced by Alcian blue periodic acid-Schiff staining. Furthermore, quantitative real-time PCR analysis revealed a significant upregulation of IL-4, IL-5, and IL-13 expression in response to BG. Conversely, the inhibitor of trained immunity reversed these effects, suggesting that BG-induced trained immunity confers strong protection against Ts infection. In conclusion, these findings suggest that BG-induced trained immunity may play a role in protection against infections caused by other helminths.

Serology survey of Ascaris suum and Trichinella spiralis in rural pigs in Southwestern Mexico.

Parasitic diseases of pigs are a public and veterinary health problem. Helminths influence pork production, whereas backyard pigs can transmit these parasites. This work aimed to investigate the prevalence of antibodies against Ascaris suum and Trichinella spiralis in backyard pigs from Jamiltepec, Region de la Costa, Oaxaca, in Southwestern Mexico. Six hundred sixty-four serum samples were obtained from backyard pigs from 23 rural villages distributed in 5 municipalities; samples were taken in a non-probabilistic manner with the owner's consent. The presence of serum antibodies against a total extract of A. suum adult worm was determined by ELISA. In contrast, antibodies to the excretion-secretion products of the T. spiralis muscle larva were determined by Western blot. The global seroprevalence for A. suum was 5.12% and 2.41% for T. spiralis; however, antibodies were only found in 8 villages and distributed in 3 municipalities. The highest frequency of positivity for Ascaris was found in the municipality of Santa Catarina Mechoacán (13.01%), whereas, in Santa María Huazalotitlán, the highest frequency of positivity for Trichinella was found (5.75%). In San Andrés, frequencies were 7.23% and 4.82%, respectively. No statistical differences were observed between populations. Our data suggest that helminth transmission is restricted by locality. However, further studies must be conducted to understand the factors limiting this transmission to promote pork meat production in parasite-free zones.

Predilection Site for the Meat Lover Trichinella spp Larvae and its Pathogenesis and Potency in Human Host

Aims: To revisited carefully previously published articles available in the internet regarding predilection site of Trichinella spp larvae including their pathogenesis and its potency. Discussion: By carefully reviewing previously published literature available in the internet regarding the parasite Trichinella tropism to its host’s striated muscle, the author briefly withdraw some important keypoint to be revealed. The nematode Trichinella spp causes serious zoonosis called trichinellosis, a disease affecting striated or skeletal muscles which consider as one of tropical disease. Even though its natural host varied, but infection among live stocks, such as pigs and other animals, which are raising public health concern. Human infection occurs after consumption of raw or undercooked meat or meat products contain muscle larvae of T. spiralis. The tropism of the parasite for individual striated muscles and/or striated muscle groups varies significantly. Trichinella spp. has a direct life cycle where all three life cycle stages (the infective muscle larvae, adult, and new born larvae) happen serially in one host only. Intestine-dwelling adults of Trichinella produce newborn larvae that bypass the enterocyte, enter the bloodstream and colonize skeletal muscle. The muscle larvae assemble excretory-secretory products which play crucial role in establishing and maintaining persistent parasitism and the host’s immune modulation and evasion. It turns out that excretory-secretory products from muscle larvae and mature worm also have hidden medical potential that can be used to treat allergic problems, inflammation-based diseases, autoimmunity and even malignancy. Conclusion: Trichinellosis is a serious and potentially fatal zoonosis which transmitted through consuming raw or uncooked contaminated meat or its comestibles. Its primary tropism is to the host’s striated muscle and infection can persist for a long time facilitated by several reciprocities of its product (e.g., excretory-secretory) with the host’s cell and immune system. Fortunately, there are several promising potency in the field of therapeutic and prevention medicine which should be explored intensely.

New records of Trichinella patagoniensis from Argentina

Trichinella spiralis was long considered the sole Trichinella species in Argentina. However, since 2004, various Trichinella species, including the encapsulated Trichinella patagoniensis and Trichinella britovi, as well as the unencapsulated Trichinella pseudospiralis, have been detected in the country. The present study aimed to identify Trichinella ML at the species level from cougars naturally infected from Argentina. To this end, muscle tissue samples from one cougar each from Córdoba, Neuquén, and Santa Cruz Provinces were individually analysed using the artificial digestion technique. DNA extraction and molecular identification of Trichinella species were conducted on individual muscle larvae by PCR amplification of the ESV region and subsequent PCR amplification and sequencing of the COI gene. Morphological analysis revealed muscle larvae with characteristics consistent with Trichinella genus. PCR revealed a single band of approximately 127 bp for each individual muscle larva. PCR amplification of the COI gene from each isolate generated a 309 bp band. Sequencing of the mitochondrial COI gene confirmed the identity of the parasite as T. patagoniensis. The present study documents new occurrences of T. patagoniensis in Puma concolor from Argentina, including the first detection of T. patagoniensis in Puma concolor from Córdoba and Neuquén Province. These findings expand the limited knowledge of T. patagoniensis distribution in Argentina.

Antiparasitic Activity of Enterocin M and Durancin-like from Beneficial Enterococci in Mice Experimentally Infected with Trichinella spiralis.

Beneficial/probiotic strains protect the host from pathogens by competitive displacement and production of antibacterial substances, i.e., bacteriocins. The antiparasitic potential of bacteriocins/enterocins and their producing strains in experimental murine trichinellosis were tested as a new therapeutic strategy. Enterocin M and Durancin-like and their producers Enterococcus faecium CCM8558 and Enterococcus durans ED26E/7 were administered daily to mice that were challenged with Trichinella spiralis. Our study confirmed the antiparasitic effect of enterocins/enterococci, which reduced the number of adults in the intestine (Enterocin M-43.8%, E. faecium CCM8558-54.5%, Durancin-like-16.4%, E. durans ED26E/7-35.7%), suppressed the Trichinella reproductive capacity ex vivo (Enterocin M-61%, E. faecium CCM8558-74%, Durancin-like-38%, E. durans ED26E/7-66%), and reduced the number of muscle larvae (Enterocin M-39.6%, E. faecium CCM8558-55.7%, Durancin-like-15%, E. durans ED26E/7-36.3%). The direct effect of enterocins on Trichinella fecundity was documented by an in vitro test in which Durancin-like showed a comparable reducing effect to Enterocin M (40-60%) in contrast to the ex vivo test. The reducing activity of T.spiralis infection induced by Enterocin M was comparable to its strain E. faecium CCM8558; Durancin-like showed lower antiparasitic activity than its producer E. durans ED26E/7.

Superb bio-effectiveness of Cobalt (II) phthalocyanine and Ag NPs adorned Sm-doped ZnO nanorods/cuttlefish bone to annihilate Trichinella spiralis muscle larvae and adult worms: In-vitro evaluation

Herein, innovative biocides are designed for the treatment of Trichinella spiralis muscle larvae (ML) and adult worms. Samarium-doped ZnO nanorods (Sm-doped ZnO) are stabilized onto the laminar structure of cuttlefish bone (CB) matrix and adorned by either Ag NPs or cobalt phthalocyanine (CoPc) species. Physicochemical characteristics of such nanocomposites are scrutinised. Adorning of Sm-doped ZnO/CB with Ag NPs shortens rod-like shaped Sm-doped ZnO nanoparticles and accrues them, developing large-sized detached patches over CB moiety. Meanwhile, adorning of Sm-doped ZnO/CB by CoPc species degenerates CB lamellae forming semi-rounded platelets and encourages invading of Sm-doped ZnO nanorods deeply inside gallery spacings of CB. Both nanocomposites possess advanced parasiticidal activity, displaying quite intoxication for ML and adult worms (≥88% mortality) within an incubation period of <48 h at concentrations around 200 μg/ml. CoPc@Sm-doped ZnO/CB nanocomposite exhibits faster killing efficiency of adult worms than that of Ag@Sm-doped ZnO/CB at a concentration of ∼75 μg/ml showing entire destruction of parasite after 24 h incubation with the former nanocomposite and just 60% worm mortality after 36 h exposure to the later one. Morphological studies of the treated ML and adult worms show that CoPc@Sm-doped ZnO/CB exhibits a destructive impact on the parasite body, creating featureless and sloughed fragments enriched with intensive vacuoles. Hybridization of cuttlefish bone lamellae by CoPc species is considered a springboard for fabrication of futuristic aggressive drugs against various food- and water-borne parasites.

Helminth-induced impairment of humoral immunity differently contribute to their anti-arthritic effects in mice: Comparison of Schistosoma mansoni and Trichinella spiralis

AimsWe have previously reported reduction of anti-type II collagen (IIC) IgG levels in collagen-induced arthritis (CIA) by Schistosoma mansoni (Sm) and Trichinella spiralis (Ts). To clarify the contribution of the impairment of humoral immunity to their anti-arthritic activities, we herein investigated the relationship between anti-IIC IgG levels and arthritic swelling in Sm- or Ts-infected mice. Methods and resultsMale DBA/1J mice were infected with Sm cercariae or Ts muscle larvae prior to the IIC immunization. In the Sm-infected mice, paw swelling and anti-IIC IgG levels were continuously lower than those of non-infected control group. In contrast, arthritic swelling in the Ts-infected mice only decreased in the early phase of CIA progression, despite the continued impairment of anti-IIC IgG production throughout the experimental period. Correlation coefficients between residual paw swelling and anti-IIC IgG titers were similar or higher in the Sm group than in the control group, but were similar or lower in the Ts group than in the control group. ConclusionThe down-modulations of anti-IIC IgG levels by the two parasitic infections and the correlation analyses suggest that the anti-arthritic activity of Sm was primarily attributed to the modulation of IgG-independent arthritogenic mechanisms and secondarily to the impairment of anti-IIC IgG production. In contrast, Ts could alleviate CIA mainly via the impairment of antibody production.

Morphological features of capsules of trichinella larvae in the muscle tissue of badgers of the Amur region

One of the main reservoirs of the causative agent of trichinosis in the Amur region is the badger, whose meat and fat are used for medicinal purposes or as a delicacy. Data on infection of badgers and the localization of Trichinella larvae in the muscle tissue of badgers are ambiguous. The morphological features of the development of muscle tissue in badgers are associated with lifestyle, which is likely reflected in the localization of Trichinella larvae in certain muscles. The goal is to determine the morphological parameters of capsules of Trichinella larvae in the muscle tissue of badgers in the conditions of the Amur region. The material was the muscle tissue of the skeletal muscles of the head, pectoral, pelvic limbs, muscles of the spinal column and abdominal cavity of badgers, hunted by hunters under licenses in the Amur region.Detection of Trichinella larvae was carried out by compressor trichinoscopy and digestion in individual housing, according to MUK 4.2.2747-10 “Methods of sanitary and parasitological examination of meat and meat products.” For each muscle, the intensity of invasion was determined (personal/gram). Morphological parameters of capsules of Trichinella larvae were determined using an eyepiece micrometer. The capsule shape index was calculated using the formula V=D/L.The most invaded muscles in badgers have been identified and the shape index of capsules of Trichinella larvae has been determined. Areas of natural foci of trichinosis in the Amur region have been identified. In badgers, the most infested Trichinella larvae are the head muscles (mylohyoid muscle, tongue muscle tissue and masticatory muscle), which are preferable to take for diagnosing trichinosis in this animal species.The rounded shape of the capsules of Trichinella larvae (shape index 0.72), characteristic of badgers of the weasel family, was established. The areas of natural foci of trichinosis have been identified - Mikhailovsky, Seryshevsky, Blagoveshchensky, Tambov and Ivanovo administrative districts of the Amur Region. Of particular concern is infection in the southern, most populated areas, where there is a high probability of the transition of trichinosis from natural foci to anthropurgic and synanthropic ones.

Nematocidal activity of chitosan nanoparticles conjugated with albendazole against the enteral and parenteral phases of trichinosis in experimentally infected mice.

Trichinosis is a serious parasitic zoonotic disease caused mainly by Trichinella spiralis. The used drugs for treatment of trichinosis showed limited bioavailability and high degree of resistance. Moreover, they have a very poor effect in treatment of encysted larvae. Therefore, there is a need for development of new agents which help in improving the bioavailability of the used drugs and enable them to reach different tissues. This study was designed to assess the use of chitosan nanoparticles (CSNPs) in conjugation with full and half dose albendazole (ABZ) in treatment of intestinal and muscular trichinosis. Albino mice (84 mice) were used to evaluate the efficacy of drugs and divided into seven groups; I: control, II: ABZ (50 mg/kg) treated, III: ABZ (25 mg/kg) treated, IV: ABZ (50 mg/kg) conjugated CSNPs treated, V: ABZ (25 mg/kg) conjugated CSNPs treated, VI: CS treated and VII: CSNPs treated. Parasitological and histopathological examinations were used to evaluate the therapeutic efficacy of the used drugs. Results showed significant reduction of adult Trichinella extracted from intestine of all ABZ treated groups either conjugated or not with the highest reduction rate in group IV followed by group V with percentage of reduction of 99.33% and 98.11%, respectively and marked improvement of histopathological examination. Also, results showed significant reduction of Trichinella larvae extracted from muscles of group IV, V and VII with the highest reduction rate in group IV with percentage of reduction of 100% in muscle larvae and marked improvement of histopathological examination. It was concluded that albendazole full dose conjugated chitosan nanoparticles can be a good candidate drug for treating both intestinal and muscular trichinosis.

*Inactivation of encysted muscle larvae of Trichinella spiralis in pigs using Mebendazole

We evaluated the effect of 4 anthelmintic treatments on the viability of Trichinella spiralis encysted muscle larvae (ML) 55 days post infection (PI) in experimentally infected pigs. Muscle larvae were isolated from pig muscle by artificial digestion after oral treatment of pigs with Levamisole (8 mg/kg, daily for 5 days) and Mebendazole (50 mg/kg, daily for 5 days); Doramectin (0.3 mg/kg, single IM injection), and Moxidectin (0.5 mg/kg, single pour on). Isolated larvae from treated pigs were orally inoculated into mice to assess viability of ML from each treatment. Only Mebendazole treatment of pigs significantly reduced ML viability in mice. The effect of timing of the effective Mebendazole treatment on ML from a longer term infection was then examined in a second experiment. Analysis revealed that Mebendazole treatment of pigs with 250 mg/kg over 3 days (83 mg/kg/day) or 5 days (50 mg/kg/day) reduced numbers of ML recovered from pig tissues compared to untreated, infected controls, and rendered ML non-infective to mice; Mebendazole treatment of pigs with 250 mg/kg in a single dose was not effective in reducing ML numbers recovered from pigs or in impacting ML infectivity to mice. An examination of the lowest effective dose of Mebendazole on encysted ML was determined in a third experiment. Mebendazole of pigs with 5, 50, or 100 mg/kg over 3 days demonstrated that 5 or 50 mg/kg over 3 days insufficient to reduce infectivity in recovered ML, while 100 mg/kg (and 83 g from experiment 2) over 3 days significantly reduces infectivity of ML. This procedure provides a means to evaluate the efficacy of various anthelmintic treatments on the viability of Trichinella spiralis ML in pig tissues, and identified Mebendazole, at 83–100 mg/kg administered over a 3–5 day period as an anthelmintic which renders encysted Trichinella spiralis ML from pig tissues non-infective. As risk from Trichinella significantly impacts acceptance of pork from pasture-raised pigs, these data provide a method, especially for producers of these high-risk pigs, to eliminate the potential of Trichinella transmission from infected pork.

Anti-obesity effects by parasitic nematode (Trichinella spiralis) total lysates.

Obesity is an inducible factor for the cause of chronic diseases and is described by an increase in the size and number of adipocytes that differentiate from precursor cells (preadipocytes). Parasitic helminths are the strongest natural trigger of type 2 immune system, and several studies have showed that helminth infections are inversely correlated with metabolic syndromes. To investigate whether helminth-derived molecules have therapeutic effects on high-fat diet (HFD)-induced obesity, we isolated total lysates from Trichinella spiralis muscle larvae. We then checked the anti-obesity effect after intraperitoneal administration and intraoral administration of total lysate from T. spiralis muscle larvae in a diet-induced obesity model. T. spiralis total lysates protect against obesity by inhibiting the proinflammatory response and/or enhancing M2 macrophages. In addition, we determined the effects of total lysates from T. spiralis muscle larvae on anti-obesity activities in 3T3-L1 preadipocytes by investigating the expression levels of key adipogenic regulators, including peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT-enhancer-binding protein alpha (C/EBPα) and adipocyte protein 2 (aP2). Oil Red O staining showed that the total lysates from T. spiralis muscle larvae decreased the differentiation of 3T3-L1 preadipocytes by decreasing the number of lipid droplets. In addition, the production levels of proinflammatory cytokines IL-1β, IL-6, IFN-γ and TNF-α were examined by enzyme-linked immunosorbent assay (ELISA). T. spiralis total lysates decreased intracellular lipid accumulation and suppressed the expression levels of PPARγ, C/EBPα and aP2. These results show that T. spiralis total lysate significantly suppresses the symptoms of obesity in a diet- induced obesity model and 3T3-L1 cell differentiation and suggest that it has potential for novel anti-obesity therapeutics.

Application of a recombinant novel trypsin from Trichinella spiralis for serodiagnosis of trichinellosis

BackgroundThe excretory/secretory (ES) antigen of Trichinella spiralis muscle larvae (ML) is currently the most widely used diagnostic antigen to detect T. spiralis infection. However, this antigen has certain drawbacks, such as a complicated ES antigen preparation process and lower sensitivity during the early phase of infection. The aim of this study was to investigate the features of a novel T. spiralis trypsin (TsTryp) and evaluate its potential diagnostic value for trichinellosis.MethodsThe TsTryp gene was cloned and recombinant TsTryp (rTsTryp) expressed. Western blotting and an enzyme-linked immunosorbent assay (ELISA) were performed to confirm the antigenicity of rTsTryp. The expression pattern and distribution signature of TsTryp at various life-cycle stages of T. spiralis were analyzed by quantitative PCR, western blotting and the immunofluorescence test. An ELISA with rTsTryp and ML ES antigens was used to detect immunoglobulins G and M (IgG, IgM) in serum samples of infected mice, swine and humans. The seropositive results were further confirmed by western blot with rTsTryp and ML ES antigens.ResultsTsTryp expression was observed in diverse T. spiralis life-cycle phases, with particularly high expression in the early developmental phase (intestinal infectious larvae and adults), with distribution observed mainly at the nematode outer cuticle and stichosome. rTsTryp was identified by T. spiralis-infected mouse sera and anti-rTsTryp sera. Natural TsTryp protease was detected in somatic soluble and ES antigens of the nematode. In mice infected with 200 T. spiralis ML, serum-specific IgG was first detected by rTsTryp-ELISA at 8 days post-infection (dpi), reaching 100% positivity at 12 dpi, and first detected by ES-ELISA at 10 dpi, reaching 100% positivity at 14 dpi. Specific IgG was detected by rTsTryp 2 days earlier than by ES antigens. When specific IgG was determined in serum samples from trichinellosis patients, the sensitivity of rTsTryp-ELISA and ES antigens-ELISA was 98.1% (51/52 samples) and 94.2% (49/52 samples), respectively (P = 0.308), but the specificity of rTsTryp was significantly higher than that of ES antigens (98.7% vs. 95.4%; P = 0.030). Additionally, rTsTryp conferred a lower cross-reaction, with only three serum samples in total testing positive from 11 clonorchiasis, 20 cysticercosis and 24 echinococcosis patients (1 sample from each patient group).ConclusionsTsTryp was shown to be an early and highly expressed antigen at intestinal T. spiralis stages, indicating that rTsTryp represents a valuable diagnostic antigen for the serodiagnosis of early Trichinella infection.Graphical

Quantitative label-free proteomic analysis of excretory-secretory proteins in different developmental stages of Trichinella spiralis

Trichinella spiralis (T. spiralis) is a zoonotic parasitic nematode with a unique life cycle, as all developmental stages are contained within a single host. Excretory-secretory (ES) proteins are the main targets of the interactions between T. spiralis and the host at different stages of development and are essential for parasite survival. However, the ES protein profiles of T. spiralis at different developmental stages have not been characterized. The proteomes of ES proteins from different developmental stages, namely, muscle larvae (ML), intestinal infective larvae (IIL), preadult (PA) 6 h, PA 30 h, adult (Ad) 3 days post-infection (dpi) and Ad 6 dpi, were characterized via label-free mass spectrometry analysis in combination with bioinformatics. A total of 1217 proteins were identified from 9341 unique peptides in all developmental stages, 590 of which were quantified and differentially expressed. GO classification and KEGG pathway analysis revealed that these proteins were important for the growth of the larvae and involved in energy metabolism. Moreover, the heat shock cognate 71 kDa protein was the centre of protein interactions at different developmental stages. The results of this study provide comprehensive proteomic data on ES proteins and reveal that these ES proteins were differentially expressed at different developmental stages. Differential proteins are associated with parasite survival and the host immune response and may be potential early diagnostic antigen or antiparasitic vaccine candidates.

SOME ENVIRONMENTAL ASPECTS OF MONITORING OF TRICHINELLOSIS IN THE KIROV REGION AND THE KOMI REPUBLIC

Background. Гельминт Trichinellа относится к классу Nematoda (Rudolphi, 1808); к отряду Trichocephalida (Skrjabin et Schulz, 1928); вид Trichinella spiralis (spiralis) (Owen, 1835) имеются также различные вариететы. В данном исследовании изучен вариетет Trichinellа spiralisIn order to prevent trichinosis in the population and animals, methods of diagnosis of trichinosis are widely used.&#x0D; Purpose. The aim of this work was to study the distribution of trichinosis among wild animals of the Kirov region and the Komi Republic and to analyze the localization of Trichinella sp. in the muscles of animals and the features of their capsules in various animal species by the methods of trichinelloscopy and the digestion of muscle tissue in artificial gastric juice.&#x0D; Materials and methods. The capsule index was calculated using morphometric analysis. The most sensitive among the methods of postmortal diagnostics is the method of digestion of muscle tissue in artificial gastric juice, therefore it is used as a method for clarifying the diagnosis in doubtful cases (sarcocystosis, alariosis).&#x0D; Results. The article provides data on the distribution of trichinosis in wild animals of the Kirov region and the Komi Republic. Information on the selective distribution of Trichinella larvae in wild animals, the morphological features of the capsules and the intensity of invasion in various animals are presented.&#x0D; Conclusion. Thus, it has been established that the distribution of Trichinella larvae in muscle depends on the species of animals and parasites.

GENERATION OF MONOCLONAL ANTIBODIES AGAINST TRICHINELLA SPIRALIS AND DETERMINATION OF THEIR IMMUNOCHEMICAL PROPERTIES

Diagnosis of trichinellosis in humans and animals is still in the developmental stage of the most effective and sensitive test for early detection. Serological methods are the most sensitive for detecting trichinella invasion. However, there is a high risk of non-specific reactions with other parasitological diseases. To address this issue, monoclonal antibodies (mAbs) against excretory-secretory antigens (ESAg) of trichinella muscle larvae are employed. In this study, hybridomas secreting mAbs against ES-Ag of Trichinella spiralis muscle larvae were generated. Out of 79 colonies, 5 mAb producer monoclonal clones (1D5, 1E7, 3C10, 4D6, 4F7) were obtained, and further stability testing selected 3 clones (1D5, 1E7, and 4F7) that yielded 14 to 40% active subclones. Western blotting using T. spiralis ES antigens demonstrated that the mAbs recognized a single band at 75 kDa. The productivity of the clones ranged from 2.0 to 4.0 mg/ml of protein. The obtained results indicate that the high activity, specificity of mAbs, and productivity of the clones recommend these mAbs for application in diagnostic purposes.

Metabolite profiling of Trichinella spiralis adult worms and muscle larvae identifies their excretory and secretory products.

Human trichinellosis is a parasitic infection caused by roundworms belonging to the genus Trichinella, especially Trichinella spiralis. Early and accurate clinical diagnoses of trichinellosis are required for efficacious prognosis and treatment. Current drug therapies are limited by antiparasitic resistance, poor absorption, and an inability to kill the encapsulating muscle-stage larvae. Therefore, reliable biomarkers and drug targets for novel diagnostic approaches and anthelmintic drugs are required. In this study, metabolite profiles of T. spiralis adult worms and muscle larvae were obtained using mass spectrometry-based metabolomics. In addition, metabolite-based biomarkers of T. spiralis excretory-secretory products and their related metabolic pathways were characterized. The metabolic profiling identified major, related metabolic pathways involving adenosine monophosphate (AMP)-dependent synthetase/ligase and glycolysis/gluconeogenesis in T. spiralis adult worms and muscle larvae, respectively. These pathways are potential drug targets for the treatment of the intestinal and muscular phases of infection. The metabolome of larva excretory-secretory products was characterized, with amino acid permease and carbohydrate kinase being identified as key metabolic pathways. Among six metabolites, decanoyl-l-carnitine and 2,3-dinor-6-keto prostaglandin F1α-d9 were identified as potential metabolite-based biomarkers that might be related to the host inflammatory processes. In summary, this study compared the relationships between the metabolic profiles of two T. spiralis growth stages. Importantly, the main metabolites and metabolic pathways identified may aid the development of novel clinical diagnostics and therapeutics for human trichinellosis and other related helminthic infections.