Evaluation of Trichinella spiralis larva group 1 antigens for serodiagnosis of human trichinellosis

Immuno-therapeutic and prophylactic potential of Trichinella spiralis antigens for inflammatory bowel diseases

Ulcerative colitis (UC), a severe chronic inflammatory disorder of the colon, is one of the inflammatory bowel diseases (IBD) that affects humans and several domestic animal species, including cats and dogs. Helminth infections and autoimmune diseases are inversely correlated, as explained by the hygiene hypothesis, which suggests that IBD is infrequent in countries where helminth infections are common but more prevalent in developed nations. This study investigated the therapeutic and prophylactic potential of Trichinella spiralis (T. spiralis) antigens in an experimental colitis model for IBD. Mice were divided into eight groups: normal model, colitis model, larval antigen prophylaxis, adult antigen prophylaxis, larval antigen therapeutic, adult antigen therapeutic, larval antigen prophylaxis and therapeutic, and adult antigen prophylaxis and therapeutic. Colitis was induced intrarectally by administering a single dose of 0.2 ml of acetic acid, except in the healthy group, which received PBS (0.2 ml). The mice were euthanized 12 days after colitis induction. The therapeutic and prophylactic potential of T. spiralis antigens were assessed through colitis severity and histopathological, immunological, and immunohistochemical examinations. The results showed a significant reduction in Disease Activity Index (DAI), an increase in goblet cells' acidic mucin levels, reduced iNOS and TNF-α expression, and decreased serum levels of IFN-γ and IL-10 cytokines in Groups IV-VIII compared to the colitis model, particularly in the group that received adult worm antigen both prophylactically and therapeutically. This study demonstrated that T. spiralis antigens, especially from adult worms, had protective and therapeutic effects on experimental colitis, with a superior effect when administered both before and after colitis induction by reducing inflammation and modulating the immune response. Thus, T. spiralis antigens may improve disease outcomes and provide a novel treatment approach for ulcerative colitis.

The Therapeutic Efficacy of Zinc Oxide Nanoparticles on Acute Toxoplasmosis in BALB/c Mice

Background

Toxoplasma gondii infects nearly one-third of the world's population. Due to the significant side effects of current treatment options, identifying safe and effective therapies seems crucial. Nanoparticles (NPs) are new promising compounds in treating pathogenic organisms. Currently, no research has investigated the effects of zinc oxide NPs (ZnO-NPs) on Toxoplasma parasite. We aimed to investigate the therapeutic efficacy of ZnO-NPs against tachyzoite forms of T. gondii, RH strain in BALB/c mice.

Methods

In an experiment with 35 female BALB/c mice infected with T. gondii tachyzoites, colloidal ZnO-NPs at concentrations of 10, 20, and 50 ppm, as well as a 50 ppm ZnO solution and a control group, were orally administered four hours after inoculation and continued daily until the mices' death. Survival rates were calculated and tachyzoite counts were evaluated in the peritoneal fluids of infected mice.

Results

The administration of ZnO-NPs resulted in the reduction of tachyzoite counts in infected mice compared to both the ZnO-treated and control group (P<0.001). Intervention with ZnO-NPs significantly increased the survival time compared to the control group (6.2±0.28 days, P-value <0.05), additionally, the highest dose of ZnO-NPs (50 ppm) showed the highest mice survival time (8.7±0.42 days).

Conclusion

ZnO-NPs were effective in decreasing the number of tachyzoites and increasing mice survival time in vivo. Moreover, there were no significant differences in survival time between the untreated control group and the group treated with zinc oxide, suggesting that, bulk ZnO is not significantly effective in comparison with ZnONPs.

Hassan A, Mohamed K, Alfaifi MS, Elshazly H, Alamri ZZ, Wakid MH, Gattan HS, Altwaim SA, Al-Megrin WAI, Younis S. Zinc oxide nanoparticles produced by Zingiber officinale ameliorates acute toxoplasmosis-induced pathological and biochemical alterations and reduced parasite burden in mice model

BACKGROUND

Although, approximately 30% of the world's population is estimated to be infected with Toxoplasma gondii (T. gondii) with serious manifestations in immunocompromised patients and pregnant females, the available treatment options for toxoplasmosis are limited with serious side effects. Therefore, it is of great importance to identify novel potent, well tolerated candidates for treatment of toxoplasmosis. The present study aimed to evaluate the effect of Zinc oxide nanoparticles (ZnO NPs) synthesized using Zingiber officinale against acute toxoplasmosis in experimentally infected mice.

METHODS

The ethanolic extract of ginger was used to prepare ZnO NPs. The produced ZnO NPs were characterized in terms of structure and morphology using Fourier Transformed Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), UV- spectroscopy and scanning electron microscopy (SEM). The prepared formula was used in treatment of T. gondii RH virulent strain. Forty animals were divided into four groups, with ten mice per group. The first group was the uninfected, control group. The second group was infected but untreated. The third and the fourth groups received ZnO NPs and Spiramycin orally in a dose of 10 mg/kg and 200 mg/kg/day respectively. The effect of the used formulas on the animals survival rate, parasite burden, liver enzymes -including Alanine transaminase (ALT) and aspartate transaminase (AST)-, nitric oxide (NO) and Catalase antioxidant enzyme (CAT) activity was measured. Moreover, the effect of treatment on histopathological alterations associated with toxoplasmosis was examined.

RESULTS

Mice treated with ZnO NPs showed the longest survival time with significant reduction in the parasite load in the livers and peritoneal fluids of the same group. Moreover, ZnO NPs treatment was associated with a significant reduction in the level of liver enzymes (ALT, AST) and NO and a significant increase in the antioxidant activity of CAT enzyme. SEM examination of tachyzoites from the peritoneal fluid showed marked distortion of T. gondii tachyzoites isolated from mice treated with ZnO NPs in comparison to untreated group. T. gondii induced histopathological alterations in the liver and brain were reversed by ZnO NPs treatment with restoration of normal tissue morphology.

CONCLUSION

The produced formula showed a good therapeutic potential in treatment of murine toxoplasmosis as demonstrated by prolonged survival rate, reduced parasite burden, improved T. gondii associated liver injury and histopathological alterations. Thus, we assume that the protective effect observed in the current research is attributed to the antioxidant capability of NPs. Based on the results obtained from the current work, we suggest greenly produced ZnO NPs as a chemotherapeutic agent with good therapeutic potential and high levels of safety in the treatment of toxoplasmosis.

Helminth Glycans at the Host-Parasite Interface and Their Potential for Developing Novel Therapeutics

Helminths are parasitic worms that have successfully co-evolved with their host immune system to sustain long-term infections. Their successful parasitism is mainly facilitated by modulation of the host immune system via the release of excretory-secretory (ES) products covered with glycan motifs such as Lewis X, fucosylated LDN, phosphorylcholine and tyvelose. Evidence is accumulating that these glycans play key roles in different aspects of helminth infection including interactions with immune cells for recognition and evasion of host defences. Moreover, antigenic properties of glycans can be exploited for improving the efficacy of anti-helminthic vaccines. Here, we illustrate that glycans have the potential to open new avenues for the development of novel biopharmaceuticals and effective vaccines based on helminth glycoproteins.

A competitive enzyme-linked immunosorbent assay for rapid detection of antibodies against Trichinella spiralis and T. britovi - one test for humans and swine

Infection with parasites from the Trichinella genus occurs in many vertebrates but disease only occurs in humans (trichinellosis). Humans are infected after the consumption of raw or undercooked meat from infected wild or domestic animals (usually swine or horses). Using the monoclonal antibody (mAb) 7C2C5, specific for an epitope unique to the muscle larvae of the genus Trichinella, we have developed a competitive enzyme-linked immunosorbent assay (c-ELISA) that enables the rapid detection of Trichinella-specific antibodies in sera originating from two different host species (human, swine) infected with either Trichinella spiralis or Trichinella britovi. This novel c-ELISA exhibited 100% specificity and sensitivity, as confirmed by a Western blot test. The assay is easy to use (one incubation step), and the time required for the procedure (45 min) is shorter than in any other ELISA format. This test could be useful for both the detection and surveillance of Trichinella infections.

Trichinella Spiralis Impact on Mesenchymal Stem Cells: Immunohistochemical Study by Image Analyzer in Murine Model

This study aims to elucidate whether Trichinella spiralis infection or its crude antigen administration can stimulate recruitment of CD105^+ve/CD45^-ve cells that could represent MSCs in intestine and skeletal muscle of experimental BALB/c albino mice compared to healthy control mice. Studied mice were divided into: 20 healthy control, 20 with orally induced T. spiralis infection, 20 received adult worm crude antigen orally and 20 received larval crude antigen intramuscular. According to specific timing schedule, mice were sacrificed and tissue sections were examined for CD105 and CD45 immunohistochemical expression using image J image analyzing software, to compare different study groups. T. spiralis infection induced a significant increase in density of CD105^+ve/CD45^-ve cells that could represent MSCs in both intestinal and muscle sections, similarly the intramuscular injected larval crude antigen caused more infiltration of such cells in muscles compared to muscle sections from healthy control mice. However, no significant difference was noticed in intestinal sections after oral adult crude antigen administration compared to healthy control mice. So, injected T. spiralis crude antigen might be a successful stimulant to MSCs attraction and recruitment in tissues nearby injection site. This could be beneficial for cell regeneration and tissue repair in case of presence of a disease induced damage.

Early detection of Trichinella spiralis DNA in the feces of experimentally infected mice by using PCR

The aim of this study was to detect Trichinella spiralis DNA in mouse feces during the early stages of infection using PCR. The target gene fragment, a 1.6kb repetitive sequence of T. spiralis genome, was amplified by PCR from feces of mice infected with 100 or 300 larvae at 3-24h post infection (hpi) and 2-28dpi. The sensitivity of PCR was 0.016 larvae in feces. The primers used were highly specific for T. spiralis. No cross-reactivity was observed with the DNA of other intestinal helminths. T. spiralis DNA was detected in 100% (12/12) of feces of mice infected with 100 or 300 larvae as early as 3hpi, with the peak detection lasting to 12-24hpi, and then fluctuating before declining gradually. By 28dpi, the detection rate of T. spiralis DNA in feces of the two groups of infected mice decreased to 8.33% and 25%, respectively. PCR detection of T. spiralis DNA in feces is simple and specific; it might be useful for the early diagnosis of Trichinella infection.

Serological tools for detection of Trichinella infection in animals and humans

Trichinellosis is a serious foodborne zoonotic disease. It is an important threat to public health in both developing and developed countries. Human infections are strongly associated with consuming undercooked meat containing infective Trichinella larvae. The development of serological tools has enabled seroepidemiological studies and contributed to our knowledge on the importance of this parasite. Serological tests can also help the diagnosis of parasite infections in humans and the surveillance of animals. Generally speaking, serological techniques include detection methods for specific antibodies and for circulating parasite antigens in the serum or tissue fluids. Here, we present a comprehensive review of various methods used in the detection of antibodies against Trichinella and circulating parasite antigens in animals and humans.

Differential immune responses in mice infected with the tissue-dwelling nematode Trichinella zimbabwensis

To improve diagnostic tools, immunotherapies and vaccine development for trichinellosis surveillance and control there is a need to understand the host immune responses induced during infection with Trichinella zimbabwensis, a tissue-dwelling nematode. In this study, we sought to determine immune responses induced in mice during T. zimbabwensis infection. The parasite strain used (Code ISS1209) was derived from a naturally infected crocodile (Crocodylus niloticus) and is the main Trichinella species prevalent in southern Africa. Sixty 6- to 8-week-old female BALB/c mice were randomly assigned to two equal groups: T. zimbabwensis-infected (n= 30) and the non-infected control group (n= 30). Levels of serum tumour necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), interleukin-4 (IL-4) as well as parasite-specific IgM, IgG, IgG1, IgG2a, IgG2b and IgG3 antibody responses were determined using enzyme-linked immunosorbent assay (ELISA). The cytokines and antibodies provided information on T-helper 1 (Th1)- and Th2-type, T-regulatory and antibody responses. Results showed that during the intestinal stage of infection, higher levels of parasite-specific IgM, IgG, IgG1 (P <  0.05) and IL-10 and TNF-α (P <  0.001) were observed in the Trichinella-infected group compared with the non-infected control group. In the parasite establishment and tissue migration phases, levels of IgG1 and IgG3 were elevated (P <  0.001), while those of IgM (P <  0.01) declined on days 21 and 35 post infection (pi) compared to the enteric phase. Our findings show that distinct differences in Th1- and Th2-type and T-regulatory responses are induced during the intestinal, tissue migration and larval establishment stages of T. zimbabwensis infection.

Proteomic analysis of Trichinella spiralis muscle larval excretory-secretory proteins recognized by early infection sera

Although the excretory-secretory (ES) proteins of Trichinella spiralis muscle larvae are the most commonly used diagnostic antigens for trichinellosis, their main disadvantage is the false negative results during the early stage of infection and cross-reaction of their main components (43, 45, 49, and 53 kDa) with sera of patients with other helminthiasis. The aim of this study was to identify early specific diagnostic antigens in T. spiralis ES proteins with 30–40 kDa. The ES proteins were analyzed by two-dimensional electrophoresis (2-DE), and a total of approximately 150 proteins spots were detected with isoelectric point (pI) varying from 4 to 7 and molecular weight from 14 to 66 kDa. When probed with sera from infected mice at 18 days postinfection, ten protein spots with molecular weight of 30–40 kDa were recognized and identified by MALDI-TOF/TOF-MS. All of ten spots were successfully identified and characterized to correlate with five different proteins, including two potential serine proteases, one antigen targeted by protective antibodies, one deoxyribonuclease (DNase) II, and one conserved hypothetical protein. These proteins might be the early specific diagnostic antigens for trichinellosis.

A bead-based suspension array for the serological detection of Trichinella in pigs

The feasibility of using bead-based suspension arrays to detect serological evidence of Trichinella in pigs was assessed. Trichinella spiralis excretory-secretory antigen was covalently coupled to paramagnetic beads and used to bind serum antibodies, which were subsequently detected using anti-swine antibody. The assay was evaluated by testing pig sera from farms where trichinellosis was endemic and comparing the results with those obtained using two commercially available ELISAs. With cut-offs established by receiver operating characteristic (ROC) analysis, digestion-negative sera from a Trichinella-free population of pigs were deemed seronegative. When anti-swine antibody was replaced with protein A/G, higher test sensitivity (94% vs. 88%) at similar test specificity (95%), was achieved. The potential use of this assay in species other than swine was also demonstrated by testing human sera.

Glycan microarray profiling of parasite infection sera identifies the LDNF glycan as a potential antigen for serodiagnosis of trichinellosis

Diagnostic methods for parasite infections still highly depend on the identification of the parasites by direct methods such as microscopic examination of blood, stool and tissue biopsies. Serodiagnosis is often carried out to complement the direct methods; however, few synthetic antigens with sufficient sensitivity and specificity are available. Here we evaluated a glycan microarray approach to select for synthetic glycan antigens that could be used for serodiagnosis of parasitic infections. Using a glycan array containing over 250 different glycan antigens, we identified GalNAcβ1-4(Fucα1-3)GlcNAc-R (LDNF) as a glycan antigen that is recognized by antibodies from Trichinella-infected individuals. We synthesized a neoglycoconjugate, consisting of five LDNF molecules covalently coupled to bovine serum albumin (BSA), and used this neoglycoconjugate as an antigen to develop a highly sensitive total-Ig ELISA for serological screening of trichinellosis. The results indicate that glycan microarrays constitute a promising technology for fast and specific identification of parasite glycan antigens to improve serodiagnosis of different parasitic infections, either using an ELISA format, or parasite-specific glycan arrays.

Validation of an enzyme-linked immunosorbent assay for diagnosis of human trichinellosis

Trichinellosis is a zoonotic disease caused by the consumption of raw or semiraw meat from different animals harboring Trichinella larvae in their muscles. Since there are no pathognomonic signs, diagnosis can be difficult; for this reason, serology is important. The objective of this study was to validate an enzyme-linked immunosorbent assay (ELISA) using excretory/secretory antigens to detect anti-Trichinella immunoglobulin G antibodies in human sera. A total of 3,505 human serum samples were tested. A receiver-operator characteristic (ROC) curve analysis was performed. The accuracy of the test was determined by calculating the area under the curve, which was equal to 0.999, indicating high accuracy. The coefficient of variation calculated for data from four serum samples in eight working sessions was no higher than 5% for the positive sera or 14% for the negative sera. Moreover, the analysis of the differences in optical density between duplicates indicated a high repeatability for the ELISA. At the ROC optimized cutoff, the sensitivity and specificity of the test were, respectively, 99.2% and 90.6% (specificity of 95.6% when excluding the samples from multiparasitized persons from Tanzania). The validated ELISA showed good performance in terms of sensitivity, repeatability, and reproducibility, whereas the specificity was limited. These results suggest that this test is suitable for detecting anti-Trichinella antibodies in human sera for diagnostic purposes, whereas its use in epidemiological surveys could be questionable.

Species-specific antibody responses to the recombinant 53-kilodalton excretory and secretory proteins in mice infected with Trichinella spp

The 53-kDa proteins in larval excretory and secretory (E-S) products were expressed from five Trichinella species (T. spiralis, T. britovi, T. nativa, T. pseudospiralis, and T. papuae), using the Escherichia coli expression system, and the antibody responses to the 53-kDa recombinant proteins in mice infected with Trichinella spp. were analyzed by Western blotting. The 53-kDa protein is conserved among the five Trichinella species, with >60% similarity in amino acid sequences. The 53-kDa recombinant proteins of T. spiralis and T. pseudospiralis reacted to sera from mice infected with T. spiralis and T. pseudospiralis at 8 days postinfection (p.i.), respectively. An antibody against the 53-kDa recombinant protein of T. spiralis recognized the 53-kDa protein in the crude extracts from adult worms and 30-day p.i. muscle larvae and E-S products from muscle larvae of T. spiralis but did not recognize any proteins from T. pseudospiralis. The sera from the mice infected with T. spiralis strongly reacted with the 53-kDa recombinant protein of T. spiralis but did not react with the 53-kDa recombinant proteins of T. britovi, T. nativa, T. pseudospiralis, and T. papuae. Similarly, the sera from mice infected with T. britovi, T. nativa, T. pseudospiralis, or T. papuae strongly reacted with the 53-kDa recombinant proteins of T. britovi, T. nativa, T. pseudospiralis, or T. papuae, respectively. These results showed that the 53-kDa recombinant proteins provide early and species-specific antibody responses in mice infected with Trichinella spp.

THE USE OF MM3 MONOCLONAL ANTIBODIES FOR THE EARLY IMMUNODIAGNOSIS OF OVINE FASCIOLIASIS

This study reports a new capture ELISA (MM3-SERO) for the serodiagnosis of sheep fascioliasis, based on the use of the monoclonal antibody (mAb) MM3. Like our previously reported indirect ELISA method, based on the use of a FPLC-purified fraction (fraction IV) of the Fasciola hepatica excretion/secretion antigens (ESAs), this new test was able to detect animals infected with very small numbers of metacercariae (5-40) and showed no cross-reaction with sera from sheep infected with other parasites, i.e., Moniezia spp., Cysticercus tenuicollis, and Dicrocoelium dendriticum. In contrast with these 2 methods, some sera (mainly those obtained from animals infected with D. dendriticum) showed high reactivities in indirect ELISA with whole F. hepatica ESAs used as control. Interestingly, the MM3-SERO ELISA has a better signal-to-noise ratio than the fraction-IV ELISA, thus allowing detection of seroconversion in infected sheep on average 1 wk earlier (3.2 +/- 0.4 wk postinfection [PI] for MM3-SERO ELISA vs. 4.2 +/- 0.9 wk PI for fraction IV ELISA). Moreover, the antibody response detected with MM3-SERO ELISA was more uniform, with seroconversion always occurring at 4 wk PI in sheep with 1-2 flukes and at 3 wk PI in sheep with more than 2 flukes. The MM3-SERO ELISA was also used to evaluate the kinetics of antibody response against MM3-recognized antigens in sera from sheep experimentally infected with F. hepatica and then treated with triclabendazole. Our results showed that antibody levels dropped by about 25% during the 4-wk observation period following the flukicide treatment, whereas they remained invariably high in all sheep left untreated. We conclude that the MM3-SERO ELISA is a 100% sensitive and 100% specific test for the early serodiagnosis of sheep fascioliasis. Preliminary studies in our laboratory seem to indicate that this method may also be useful for the determination of anti-F. hepatica antibodies in serum and milk of other ruminants. A commercial version of MM3-SERO is currently available from BIO X Diagnostics (La Jemelle, Belgium).

TSL-1 antigens of Trichinella: An overview of their potential role in parasite invasion, survival and serodiagnosis of trichinellosis

The majority of studies on the immunobiology of Trichinella species have centred on the larval muscular phase (L1) with a view to identifying immunodominant antigens located on the surface of the cuticle and in the larval secretions; the nucleus of the parasite-host interaction. These antigens have been classified as eight groups (TSL-1-TSL-8), of which those belonging to the group TSL-1 have been most intensely studied. The principal constituents are glycoproteins, glycan carriers that contain a unusual sugar, the tyvelose (3,6-dideoxy-d-arabinohexose). Studies aimed at improving serodiagnostic techniques to detect trichinellosis indicate that these antigens are ideal candidates. They are capable of inducing a strong humoral response involving the generation of specific antibodies against beta-tyvelose, a sugar that seems to be exclusive to the Trichuroidea. Furthermore, these glycoproteins appear to fulfil an important function in the development and maintenance of the parasite in the muscular niche, and they appear to be fundamental for the invasion of the intestinal epithelium. It has also been demonstrated that specific monoclonal antibodies against tyvelose can mediate a degree of immunoprotection in the rat through the phenomenon known as rapid expulsion.

Comparative analysis of Trichinella spiralis and Trichinella nativa proteins by two-dimensional gel electrophoresis

Trichinella spiralis and Trichinella nativa are both common wildlife parasites in Finland. However, they differ substantially in their resistance to below 0 degrees C temperatures in their natural hosts. T. nativa can live in frozen fox meat for years, whereas T. spiralis dies when frozen. In mouse muscle, the difference is not as evident; even T. nativa cannot maintain infectivity when kept at -20 degrees C for 1 week. Crude larval protein extracts of these two parasite species were analyzed by two-dimensional gel electrophoresis (2DE). The protein patterns showed clear differences, but matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) peptide mass fingerprint followed by database searches failed to identify these proteins, suggesting that they may still be uncharacterized. The patterns compared after freezing treatment at -20 degrees C revealed changes in the intensity of some protein spots. The antigenic differences of the species were analyzed with two-dimensional Western blots, which showed T. spiralis-specific proteins.