IgG antibody responses in early experimental sparganosis and IgG subclass responses in human sparganosis

Establishment of Animal Infection Model of Spirometra Mansoni and Identification of Spirometra Mansoni by Enzyme-Linked Immunosorbent Assay

Objective: Spirometra mansoni is a crucial zoonotic parasite. Its larvae are more harmful than adult worms due to their ability to migrate through the host's tissues and organs. Therefore, it is necessary to establish an animal model of spargana for observing pathological changes and exploring diagnostic techniques. Methods: In this study, we infected Kunming mice and cats without any pathogens by feeding sparganum (with the scolex and neck) in order to understand the infection cycle of S. mansoni and explore the preservation host of sparganosis. The infection of S. mansoni was determined by fecal detection and enzyme-linked immunosorbent assay (ELISA). Results: In the model of cats, the eggs of S. mansoni were found in the feces ten days after the infection. The serum-specific IgG antibodies against S. mansoni were positive in experimental groups (mice and cats), and after sixty days, the S. mansoni worms isolated from experimental groups were collected. Conclusion: In conclusion, the experimental results show that mice and cats can be stably infected with S. mansoni through feeding sparganum (with the scolex and neck). The infection method of this study has the potential to establish a practical model for investigating the diagnostic process of S. mansoni, laying the groundwork for application and development. ELISA was used to diagnose mice and cats infected with sparganosis mansoni, providing a case for non-invasive identification of animal sparganosis.

Evaluation of serum protein electrophoresis and immunofixation in dogs seropositive for various vector-borne pathogens

BACKGROUND

Canine vector-borne diseases (VBDs) induce non-specific dysproteinemias, detectable by serum protein electrophoresis (SPE). VBDs have been reported to induce a monoclonal gammopathy pattern. Monoclonal gammopathies are commonly the result of paraprotein (M-protein) produced by an immunoglobulin-secreting neoplasm.

OBJECTIVES

The aims of this study were to characterize and compare SPE and immunofixation (IF) changes, evaluate the performance of previously identified SPE and IF interpretative criteria, and identify M-proteins in a cohort of dogs seropositive for a VBD and with an unknown history for an immunoglobulin-secreting neoplasm.

METHODS

A total of 143 serum samples from dogs that tested seropositive for different vector-borne pathogens were assessed by SPE. Cases with abnormal globulin fractions were further characterized by IF. Protein fraction and IF labeling results were evaluated using Kruskal-Wallis with Dunn's multiple comparisons and principal component analysis (PCA).

RESULTS

IF was performed in 112 VBD-seropositive samples with dysproteinemia evaluated by SPE. Most (84/112, 75%) had a polyclonal expansion. Only two dogs had findings suggestive of an M-protein when considering both SPE and immunofixation. PCA clustered E.canis/A.phagocytophilum and B.gibsoni/CM.haematoparvum groups with relatively more γ-globulins than albumin and α-globulins, and the B.gibsoni/CM.haematoparvum group with more prominent IgA and IgM labeling than IgG labeling. Additionally, D.immitis clustered with more prominent β-globulins than γ-globulins and more IgG4 than IgG-FC.

CONCLUSIONS

The previously derived interpretative criteria suggested an M-protein in very few VBD-seropositive dogs. PCA identified SPE and immunofixation pattern differences between dogs seropositive for different infectious agents.

Immunoglobulin G4-related disease in a dog

Immunoglobulin G4-related disease (IgG4-RD), which affects many organ systems, has been recognized as a distinct clinical entity in human medicine for just over a decade but has not been previously identified in dogs. In humans, IgG4-RD is characterized by diffuse IgG4-positive lymphoplasmacytic infiltrates that commonly lead to increased serum concentrations of IgG4 and IgE, peripheral eosinophilia, tumorous swellings that often include the parotid salivary glands, obliterative phlebitis, and extensive fibrosis. Herein we describe the diagnosis, clinical progression, and successful treatment of IgG4-RD in an 8-year-old female spayed Husky mixed breed dog. Immunoglobulin G4-related disease should be considered as a differential diagnosis for dogs with vague clinical signs, lymphoplasmacytic swellings, restricted polyclonal gammopathy, eosinophilia or some combination of these findings.

Pulmonary sparganosis mansoni: a case report from a non-endemic region

Sparganosis mansoni is a parasitic disease caused by the larva of Spirometra mansoni. It occurs worldwide, but only a few patients show pulmonary involvement. Here, we present a case of pulmonary sparganosis mansoni in a non-endemic region. A 32-year-old Chinese woman presented with intermittent bloody phlegm, peripheral blood eosinophilia, and migratory patch shadows in both lungs. She had been misdiagnosed with eosinophilic pneumonia. She had a history of eating raw frogs, and the sparganum mansoni antibody was positive in both her blood and bronchoalveolar lavage fluid. Several sparganum mansoni were found in a frog sample that the patient provided. Consequently, she was diagnosed with pulmonary sparganosis mansoni. After two oral courses of praziquantel were administered, her symptoms and radiological lesions improved significantly. To our knowledge, this is the first case of pulmonary sparganosis mansoni occuring in Shanghai. Oral praziquantel is effective for the treatment of sparganosis mansoni, although its course of therapy may need to be repeated.

Immunoproteomic Analysis of the Excretory-Secretory Proteins from Spirometra mansoni Sparganum

BACKGROUND

Sparganosis is caused by the invasion of Spirometra sparganum into various tissues/organs. Subcutaneous sparganosis can be diagnosed by biopsy, while visceral/cerebral sparganosis is not easy to be diagnosed. The diagnosis depends largely on the detection of specific anti-sparganum antibodies. The specificity of the ELISA could be increased by using S. mansoni sparganum excretory-secretory (ES) antigens, but it also had the cross-reactions with sera of patients with cysticercosis or paragonimiasis. The aim of this study was to identify early specific diagnostic antigens in S. mansoni sparganum ES proteins.

METHODS

The sparganum ES proteins were analyzed by two-dimensional electrophoresis (2-DE) and Western blot probed with early sera from infected mice at 14 days post-infection. The immunoreactive protein spots were characterized by MALDI-TOF/ TOF-MS.

RESULTS

A total of approximately 149 proteins spots were detected with isoelectric point (pI) varying from 3 to 7.5 and molecular weight from 20 to 115 kDa and seven protein spots with molecular weight of 23-31 kDa were recognized by the infection sera. Three of seven spots were successfully identified and characterized as the same S. mansoni protein (cysteine protease), and the proteins of other 4 spots were not included in the databases.

CONCLUSION

The cysteine protease from S. mansoni ES proteins recognized by early infection sera might be the early diagnostic antigens for sparganosis.

A protein microarray for the rapid screening of patients suspected of infection with various food-borne helminthiases

Background

Food-borne helminthiases (FBHs) have become increasingly important due to frequent occurrence and worldwide distribution. There is increasing demand for developing more sensitive, high-throughput techniques for the simultaneous detection of multiple parasitic diseases due to limitations in differential clinical diagnosis of FBHs with similar symptoms. These infections are difficult to diagnose correctly by conventional diagnostic approaches including serological approaches.

Methodology/Principal Findings

In this study, antigens obtained from 5 parasite species, namely Cysticercus cellulosae, Angiostrongylus cantonensis, Paragonimus westermani, Trichinella spiralis and Spirometra sp., were semi-purified after immunoblotting. Sera from 365 human cases of helminthiasis and 80 healthy individuals were assayed with semi-purified antigens by both a protein microarray and the enzyme-linked immunosorbent assay (ELISA). The sensitivity, specificity and simplicity of each test for the end-user were evaluated. The specificity of the tests ranged from 97.0% (95% confidence interval (CI): 95.3–98.7%) to 100.0% (95% CI: 100.0%) in the protein microarray and from 97.7% (95% CI: 96.2–99.2%) to 100.0% (95% CI: 100.0%) in ELISA. The sensitivity varied from 85.7% (95% CI: 75.1–96.3%) to 92.1% (95% CI: 83.5–100.0%) in the protein microarray, while the corresponding values for ELISA were 82.0% (95% CI: 71.4–92.6%) to 92.1% (95% CI: 83.5–100.0%). Furthermore, the Youden index spanned from 0.83 to 0.92 in the protein microarray and from 0.80 to 0.92 in ELISA. For each parasite, the Youden index from the protein microarray was often slightly higher than the one from ELISA even though the same antigen was used.

Conclusions/Significance

The protein microarray platform is a convenient, versatile, high-throughput method that can easily be adapted to massive FBH screening.

Food-borne helminthiases (FBHs) have caused significant problems in public health and also posed socio-economic concerns. Common FBHs, such as cysticercosis, trichinellosis, paragonimiasis, sparganosis and angiostrongyliasis, have a worldwide distribution with high morbidity and even death. The objective of the present study was to develop and test a rapid assay suitable for large-scale screening for FBHs that would also allow differential diagnosis between the various parasite species. We tested archived, well-characterized serum specimens and prioritized tests for future evaluation in rapid and simultaneous screening of five different FBHs, i.e. cysticercosis, trichinellosis, paragonimiasis, sparganosis and angiostrongyliasis. This was done with a multiplex protein microarray assay equipped with semi-purified antigens capable of detecting disease-specific antibodies. Results showed that the protein microarray developed displayed a good specificity, ranging from 97.0% to 100.0%, and a sensitivity, ranging from 85.7% to 92.1%, with a Youden index variation from 0.83 to 0.92. It was concluded that the protein microarray provides a sensitive, high-throughput technique for the simultaneous detection of multiple FBHs overcoming the limitations of conventional diagnostics.

Suppression of IP-10/CXCL10 gene expression in LPS- and/or IFN-γ-stimulated macrophages by parasite-secreted products

T helper (Th)2 polarized immune responses are characteristically dominant in helminth infections. The gene expression of interferon (IFN)-γ-inducible protein 10 (IP-10/CXCL10), which promotes Th1 responses, in mouse macrophages stimulated with lipopolysaccharide (LPS) and/or IFN-γ was suppressed by excretory/secretory (ES) products of Spirometra erinaceieuropaei plerocercoids. ES products suppressed LPS- and/or IFN-γ-induced transcriptional activities of a luciferase reporter gene under the control of a 243-bp fragment of the IP-10 gene promoter/enhancer, which contains an IFN-stimulated response element (ISRE) and two κB elements. Consistent with this result, ES products inhibited ISRE-dependent heterologous promoter activities and LPS- or IFN-γ-induced ISRE-binding activity. ES products also suppressed LPS-induced IFN-β gene expression. Furthermore, ES products suppressed nuclear factor (NF)-κB RelA (p65)-dependent transcriptional activity, whereas ES products had no effect on the κB-binding activity. These results suggest that ES products suppress the IP-10 gene expression by inhibiting the ISRE- and RelA-dependent transcriptional activities in mouse macrophages.

Two-dimensional immunoblot analysis of antigenic proteins of Spirometra plerocercoid recognized by human patient sera

Sparganosis is caused by invasion of Spirometra plerocercoid into various tissues/organs. Subcutaneous sparganosis can be diagnosed and treated by worm removal, while visceral/cerebral sparganosis is not easy to diagnose. The diagnosis depends largely on the detection of specific antibodies circulating in the patients' sera. Previous studies demonstrated that 31 and 36kDa proteins of the sparganum invoked specific and sensitive antibody responses, but also showed cross reactions with cysticercosis sera. We enriched protein fractions containing 31-36kDa through gel filtration and examined immune recognition pattern against the patient sera by 2-dimensional electrophoresis (2-DE) followed by immunoblotting. Serum samples from sparganosis patients recognized 8-10 protein spots of 31 and 36kDa with different isoelectric point (pI) values with variable combinations, in which four spots of 31kDa with pIs 3.4, 3.9, 4.0 and 4.1, and one 36kDa spot (pI 3.5) appeared to be specifically reactive. One 31kDa protein spot with pI 3.3 and two spots of 36kDa with pIs 3.3 and 3.5 reacted crossly with neurocysticercosis sera. Neither sera from patients with other parasitic infections nor those from healthy controls showed positive reaction. Two-DE/immunoblot analysis might be highly available in differential serodiagnosis of human sparganosis.

Production of polyclonal antibodies against the tegument of sparganum (plerocercoid of Spirometra mansoni) and its immunolocalization

In a previous study, the author developed a method for separation of the tegument of spargana (plerocercoids of Spirometra mansoni) from the parenchyme using urea. The present study, as a next step, was performed to evaluate which molecules are present in the outer tegument. Two major proteins, 180 and 200 kDa, are present in the tegument and we could make polyclonal antibodies against these molecules. Their immunolocalization was processed and the outermost layer of the spargana showed strong positive staining. Conclusively, we could confirm that the 180 and 200 kDa molecules might be tightly bound membrane proteins in the tegument of spargana.

Diagnostic values of IgG4 in human gnathostomiasis

The diagnostic values of immunoglobulin G subclass antibodies from patients with gnathostomiasis were assessed by immunoblot technique. Antigen was prepared from crude extracts of Gnathostoma spinigerum advanced third-stage larvae obtained from naturally infected eels. The sera were obtained from 14 parasite-confirmed gnathostomiasis cases, 63 patients with other helminthic infections and 13 healthy controls. Nine prominent IgG4 reactive bands appeared with molecular weights of 94, 51, 47, 43, 38, 24, 21, 20 and 15 kDa. The diagnostic sensitivity of each of the nine reactive bands ranged from 100% to 64.3% in 14 parasite-confirmed gnathostomiasis cases. All (100%) confirmed cases recognized the 21 kDa antigenic band, but not other helminthic infections or parasite-free control. Recognition of 21 kDa antigen in G. spinigerum advanced third-stage larvae crude extracts is the most specific diagnostic marker for human gnathostomiasis, with 100% sensitivity and specificity. The 20 and 24 kDa protein bands were additional diagnostic bands for confirming diagnosis of infection where the 21 kDa band was faint. No specific binding of IgG1, IgG2, or IgG3 antibodies was observed in any sera from confirmed gnathostomiasis cases.