[Establishment of an animal model of Sparganum mansoni infection and study on therapeutic methods â Establishment of an animal model of Sparganum mansoni infection in mice and changes of serum specific antibody levels post-infection].

OBJECTIVE: To establish an animal model of Sparganum mansoni (plerocercoid larva of S. mansoni) infection in mice and observe the changes of blood routine examinations and serum anti-sparganum antibody levels after the infection. METHODS: The spargana tapeworms were collected from frogs, and 25 Kunming mice were orally infected with the Sparganum tapeworms (3 tapeworms/mouse). Two days before the infection and 2, 7, 14, 21, 28, 35, 42 days and 49 days after the infection, the peripheral blood samples of mice were collected for the blood routine examinations and the detections of anti-S. mansoni IgG antibody with ELISA. Forty-nine days after the infection, all the mice were sacrificed to find out the Sparganum tapeworms in the bodies of mice. RESULTS: The count of the total white blood cells was significantly elevated on the second day of the mice infected with Sparganum. The serum anti-Sparganum antibody was detected on the 14th day of the infection in some mice, and on the 21st day of the infection, the serum anti-Sparganum antibody was detected in all the mice. After the mice were sacrificed, the Sparganum tapeworms were found out in many tissues and organs, and especially in the subcutaneous tissues and muscle. CONCLUSIONS: The establishment of animal model of Sparganum infection is successful in mice with the oral method, and white blood cells and serum specific IgG antibody detection can be used as auxiliary diagnosis methods of S. mansoni infection.

Seroprevalence of Sparganosis in Rural Communities of Northern Tanzania.

In this study, the seroprevalence of sparganosis and its relationship with sociodemographic factors in northern Tanzania have been assessed. A total of 216 serum samples from two rural districts, Monduli and Babati, were tested for sparganosis using an enzyme-linked immunosorbent assay. The seroprevalence of anti-sparganum IgG antibodies was 62.5% (95% confidence interval [CI] = 56.1-68.9) in all age groups. There were significant associations between district (relative risk [RR] = 1.95, 95% CI = 1.42-2.69), education (RR = 1.40, 95% CI = 1.15-1.70), and pet ownership with seropositivity (RR = 1.48, 95% CI = 1.02-2.16) based on univariate analysis. However, only the district was significantly associated with seropositivity (odds ratio = 4.20, 95% CI = 1.89-9.32) in binary logistic regression analysis. Providing health education to people residing in sparganosis-endemic areas is likely to improve the efficacy of preventative measures and reduce human disease burden.

Serodiagnosis of sparganosis by ELISA using recombinant cysteine protease of Spirometra erinaceieuropaei spargana.

The Spirometra erinaceieuropaei cysteine protease (SeCP) gene encoding a 36 kDa protein was expressed in Escherichia coli, and the potential of recombinant SeCP protein (rSeCP) as an antigen for the serodiagnosis of sparganosis was investigated by ELISA and compared with those of ELISA with sparganum excretory-secretory (ES) antigens. The sensitivity of rSeCP-ELISA and ES-ELISA was 96.67 % (29/30) and 100 % (30/30) respectively, for the detection of anti-sparganum IgG antibodies in sera of the experimentally infected mice (P > 0.05), and the specificities of both ELISA were 100 % (77/77). In heavily, moderately, and lightly infected mice (five, three, and one larvae per mouse), anti-sparganum antibodies were firstly detected by rSeCP-ELISA at 10-12 days post-infection (dpi), respectively, and then continued to increase with a detection rate of 100 % at 14-22 dpi. In three groups of infected mice, the anti-sparganum antibody levels at different times after infection were statistically different (P < 0.05). The results showed that the rSeCP might be a potential candidate antigen for early and specific serodiagnosis of sparganosis. But, it needs to be further evaluated with sera of the patients with sparganosis and other helminthiasis.

Identification of early diagnostic antigens from Spirometra erinaceieuropaei sparganum soluble proteins using immunoproteomics.

In order to identify early specific diagnostic antigens of Spirometra erinaceieuropaei (syn. S. erinacei or S. mansoni) sparganum, soluble proteins were analyzed by two-dimensional electrophoresis (2-DE) and western blotting probed with immune sera from infected mice at 14 days post-infection. From a total of approximately 462 proteins spots mainly distributed in pI range of 5-6.6 and with molecular mass of 25-48 kDa, 6 immuno-reactive protein spots with molecular mass of 31.8-38.3 kDa were characterized by MALDI-TOF/TOF-MS. Three proteins were identified as S. erinaceieuropaei cysteine protease, Toxoplasma gondii hypothetical protein and Pecten spp actin, while the remaining were unidentified. The cysteine protease from S. erinaceieuropaei soluble proteins recognized by early infection sera might be developed as diagnostic reagent for early detection of sparganosis.

Functional changes in regulatory T cells during an experimental infection with sparganum (plerocercofid of Spirometra mansoni).

Regulatory T (Treg) cells are important in the regulation of immune response, but the exact regulation of Treg-cell function in vivo is still not well known. In the present study, we investigated the functional activity of CD4(+) CD25(+) Treg cells as well as the frequency and number of CD4(+) CD25(+) FoxP3(+) Treg cells in the spleens of experimentally infected mice with a tissue-migrating parasite, sparganum (plerocercoid of Spirometra mansoni) for 3 weeks. The results demonstrated fluctuations in the Treg-cell function during the parasite infection, being up-regulated at day 3, down-regulated until day 14, and thereafter up-regulated again at day 21. We also investigated the cytokine-producing capability of the splenocytes to study the pattern of immune response of the mice to the parasite. The results showed decreased capabilities of interleukin-2 (IL-2), interferon-γ (IFN-γ) and IL-17α production, whereas IL-4-producing and IL-10-producing capabilities were increased along with the parasitic infection. Meanwhile, IL-6-producing capability was increased to reach a peak at week 2, and thereafter was decreased to the baseline level. As a regulatory mechanism, we found that Treg-cell function was attenuated in the presence of the crude extracts of sparganum, but was enhanced in the presence of the excretory-secretory products, suggesting that sparganum products were involved in the triggering and regulation of immune response in the acute and chronic phases, respectively. Results show that Treg cells are central in the immune homeostasis in vivo that is maintained by host-parasite interactions during the parasitic infection.

Expression of TNF-α and IL-1ß in splenic dendritic cells and their serum levels in mouse sparganosis.

Sparganosis is a tissue invading helminthiasis infecting intermediate hosts, including humans. Strong immune responses are expected to occur in early phases of infection. Thus, we investigated cytokine expressions in splenic dendritic cells and in sera after experimental infection of mice. In splenic dendritic cells, TNF-α and IL-1ß expression peaked at week 1 and week 3 post-infection (PI), respectively, and also early phase (week 2 PI) depressed cytokine expression was noticed. Serum IL-1ß concentration increased significantly at week 2 PI and peaked at week 6 PI, and that of TNF-α peaked at week 6 PI. These results showed that pro-inflammatory cytokines, TNF-α and IL-1ß, are chronologically regulated in mouse sparganosis.

Serodiagnosis of experimental sparganum infections of mice and human sparganosis by ELISA using ES antigens of Spirometra mansoni spargana.

We conducted a study of serodiagnosis of experimental sparganum infections of mice and human sparganosis by enzyme-linked immunosorbent assay (ELISA) using excretory-secretory (ES) antigens of Spirometra mansoni spargana and compared the sensitivity and specificity of crude and ES antigens for detecting the specific anti-sparganum IgG antibodies. By crude antigen ELISA and ES antigen ELISA, anti-sparganum IgG was detected in all of 30 serum samples of the infected mice; no cross-reactions were observed in serum samples of the mice infected with Trichinella spiralis, Schistosoma japanicum, Toxoplasma gondii, and normal mice. Anti-sparganum IgG was detected by ES antigen ELISA in sera of mice infected with one, two, four, six, and eight spargana at 3 weeks post-infection (wpi), with a detection rate of 100%, and lasted to 18 wpi when the experiment was ended. The difference in anti-sparganum antibody levels among five groups of the infected mice was statistically significant (F=245.296, p<0.05); the antibody levels were correlated with infecting doses of spargana (r=0.323, p<0.05). The sensitivity of both ELISA in detecting the serum samples of patients with sparganosis was 100% (20/20), but 96.72% (59/61) of specificity of ES antigen ELISA in detecting serum samples of patients with cysticercosis, echinococcosis, paragonimiosis, clonorchiosis, and schistosomiasis, and healthy persons was significantly greater than 72.13% (44/61) of crude antigen ELISA (χ (2) = 14.027, p<0.05). Our finding indicates that ELISA using ES antigens of S. mansoni spargana may be applied to the specific early serodiagnosis of sparganosis.

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

Antigenic components in the crude extracts of Spirometra mansoni plerocercoid were analyzed in early experimental infections and in IgG subclass observed in clinical sparganosis. By IgG immunoblot, sera obtained serially from experimental mice, fed 5 spargana each, were reacted with the crude extracts. Protein bands at 36-26 kDa and 103 kDa showed positive reactions since two weeks after infection. In a differential immunoblot, in which a monospecific antibody against sparganum chymase at 36 kDa was pre-treated, the reactions at 36-26 kDa disappeared, indicating that the sparganum chymase and its degradation products invoked IgG antibody reactions. When 69 patients sera of human sparganosis were examined for their IgG subclass responses, IgG4 levels showed the highest reaction which was followed by IgG1. The IgG4 antibody also reacted mainly with 36-31 kDa protease. These results indicate that 36 kDa chymase of S. mansoni plerocercoid is the main antigenic component inducing IgG antibody response in early stage of experimental sparganosis and for specific IgG subclass reactions in human sparganosis.

A neutral cysteine protease of Spirometra mansoni plerocercoid invoking an IgE response.

When crude extracts of Spirometra mansoni plerocercoid (sparganum) were analysed by SDS-polyacrylamide gel electrophoresis (PAGE)/immunoblot using patients' sera, IgE antibodies reacted specifically with 21, 27 and 53 kDa proteins. The 21 and 27 kDa proteins have been previously characterized as cysteine proteases. In this study, the 53 kDa protein was confirmed, by immunoprecipitation, to induce a specific IgE response. The protein was purified by affinity chromatography using an IgG1 (kappa 2) type mAb. The protein was partially sensitive to peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F (endo F) digestion. It exhibited an endoproteinase activity in a thiol-dependent manner preferentially degrading benzoyloxycarboxyl-phenylalanyl-arginyl-4- methoxy-beta-naphthylamide (Z-phe-arg-MNA) of a panel of substrates tested. This endoprotease activity was maximal at pH 6.5 and in 0.1 M sodium phosphate. The proteolytic activity was inhibited by 10(-5) M L-trans-epoxysuccinyl-L- leucylamido-(4-guanidino)butane (E-64) and 1 mM iodoacetamide (IAA), and potentiated by dithiothreitol (DTT, 5 mM).

Cerebral sparganosis: clinical manifestations, treatment, and outcome.

Cerebral sparganosis is a rare parasitic disease caused by infestation by the plerocercoid larva of Spirometra mansoni. The authors retrospectively analyzed 17 cases of cerebral sparganosis treated at Seoul National University Hospital between 1986 and 1994. The patients' ages at diagnosis ranged from 6 to 57 years (median 32 years) and the male/female ratio was 13:4. Diagnosis was based on radiological findings, serological test results, operative findings, and histopathological examinations. Characteristic magnetic resonance (MR) findings consisted of widespread white matter degeneration and cortical atrophy, mixed-signal lesion (low in the central and high in the peripheral regions on T2-weighted images) with irregular dense enhancement of central foci and changes in the location and shape of the enhancing lesion in follow-up studies. Ten patients underwent surgical removal of the parasitic lesion, six received medical treatment alone (five with praziquantel and one with antiepileptic drugs), and one underwent insertion of a ventriculoperitoneal shunt and a course of praziquantel. Follow-up periods ranged from 13 to 111 months (mean 49 months). Seven patients who underwent complete removal of the lesion, live worm, or degenerative worm with surrounding granuloma showed a favorable course. Patients who received medical treatment alone or incomplete removal exhibited progression in their neurological deficits and their seizures could not be controlled. Medication with praziquantel seemed to have no killing effect on live worms. The authors conclude that MR imaging is the most valuable modality for the early detection of cerebral sparganosis and that complete surgical removal of granuloma together with worms, whether they are alive or degenerative, is the treatment of choice.

Cleavage of immunoglobulin G by excretory-secretory cathepsin S-like protease of Spirometra mansoni plerocercoid.

When immunoglobulin G (IgG) was incubated with Spirometra mansoni plerocercoid (sparganum), it was cleaved into Fab and Fc fragments. Fab/c fragments were also hydrolysed. The digestion was accelerated by dithiothreitol (DTT), indicating that cleavage of IgG heavy chain was due to a cysteine protease secreted into the medium. The responsible enzyme, of M(r) 27 (+/- 0.8) kDa, was purified by a series of thiopropyl affinity, Sephacryl S-300 HR and DEAE-anion exchange chromatographies, either from worm extracts or from excretory-secretory products (ESP). The purified, thiol-dependent protease showed an optimal activity at pH 5.7 with 0.1 M sodium acetate but was active over the pH range 4.5-8.0. Its activity was inhibited completely by 10(-5) M L-trans-epoxysuccinylleucylamido(4-guanidino) butane (E-64) and 1 mM iodoacetamide (IAA), but by only 53% using the specific cathepsin L inhibitor, Z-Phe-Phe-CHN2 (5 x 10(-5) M). Partial NH2-terminal amino acid sequence was Leu-Pro-Asp-Ser-Val-Asn-Trp-Arg-Glu-Gly-Ala-Val-Thr-Ala-Val which showed 80% homology to human cathepsin S. Immunoblot analysis showed that sera from infected patients exhibited IgE antibody reaction. It is proposed that cleavage of immunoglobulin by an excreted-secreted, cathepsin S-like, allergenic protease is a mechanism of immune evasion used by the sparganum.

Purification and partial characterization of cysteine proteinase from Spirometra mansoni plerocercoids.

Spirometra mansoni plerocercoids were dissected from the tissues of naturally infected snakes (Natrix trigrialateralia). Fresh plerocercoids were incubated in medium, and excretory-secretory products (E-S) were collected. In addition, soluble proteins from lyophilized plerocercoids (10 mg/ml) were extracted in 0.1 M sodium acetate. Proteinase activity was assayed with a synthetic fluorescent substrate, carbobenzoxy-phenylalanyl-arginyl-7-amino-4-trifluoromethylcoumarin. Proteinase was isolated from plerocercoid extract or E-S by diethylaminoethyl trisacryl M ion-exchange chromatography and thiolpropyl-Sepharose affinity chromatography. These separations resulted in a 12.2- (extract) and 15.6-fold (E-S) purification of proteinase. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified materials revealed a 28-kDa band, consistent with the apparent native molecular weight (gel filtration chromatography) of approximately 35 kDa. Proteinases purified from whole extracts and E-S were compared for various biochemical characteristics; inhibitor profiles indicated that activities from both sources are cysteine proteinases, they exhibited identical pH curves with optima at pH 5.5 and a 50% activity range at pH 4.7-8.0, they cleaved collagen chains to 3 identical products, and they showed only minor activity toward hemoglobin. Further, the proteinase purified from plerocercoids was utilized in immunoblots with sera from sparganosis patients. Antibody (IgG) from the infected patients, but not uninfected controls, recognized the cysteine proteinase, suggesting that this antigen may be useful in the serodiagnosis of Spirometra mansoni infection.

The fate of spargana inoculated into the cat brain and sequential changes of anti-sparganum IgG antibody levels in the cerebrospinal fluid.

To establish an animal model of intracranial sparganosis, the fate and behavior of the experimentally inoculated spargana were observed. A total of 102 scolices of spargana were injected into 22 cat brains, and the cats were sacrificed at 2 weeks, 1 month, 3 months and 6 months after the inoculation. Neurosparganosis was established in 77% of the cats. Of 43 recovered worms, 19 (44%) were located in the subdural or subarachnoid space, 16 (37%) in the brain parenchyme, and 2 (5%) in the lateral ventricle. One was detected at the diploic space of the skull and 5 were outside the cranial cavity. All but one were alive, and had grown tails. They were distributed in the brain parenchyme randomly. There was no place which they could not invade. No adult was found in the intestine. Cerebrospinal fluid (CSF) was collected before inoculation, 1 week, 2 weeks, 1 month, 3 months and 6 months after inoculation. The level of anti-sparganum IgG antibody in CSF measured by ELISA began to increase above the criteria of positivity 1 month after inoculation. Three months after inoculation, the values markedly increased. The present findings reveal that intracranial inoculation of spargana into the brains of cats would be a good animal model of experimental neurosparganosis.

Leukocyte accumulation in sparganosis: demonstration of eosinophil and neutrophil chemotactic factors from the plerocercoid of Spirometra erinacei in vivo and in vitro.

In order to determine whether the plerocercoid of Spirometra erinacei itself has eosinophil and neutrophil chemotactic factors, in vivo and in vitro examinations were carried out. We could observe large numbers of eosinophils and neutrophils which accumulated at the injection site of normal guinea pig skin following intradermal injection of soluble extract of plerocercoids of S. erinacei. At 1 hour after the injection, neutrophils appeared at the site, and the cell number reached its peak at 4 hours. Eosinophils appeared rather later than neutrophils (at 2-4 hours), and the number of cells reached its peak at 8 hours after the injection. Eosinophil and neutrophil chemotactic activities were also confirmed in an in vitro system by using a blind-well chemotaxis chamber with a Millipore filter in dose dependent fashion. An eosinophil chemotactic factor (ECF) with molecular weight of approximately 15,000, and two different neutrophil chemotactic factors, one of about same molecular weight as the ECF and the other of low molecular weight, were demonstrated by gel filtration on Sephadex G-200. Furthermore, it was confirmed that those factors were released from parasite by the detection of intensive eosinophil and neutrophil chemotactic activities in the culture supernatants containing plerocercoids.

Comparison of the effects of the growth factor produced by Spirometra mansonoides and growth hormone in diabetic-hypophysectomized rats: lymphoid tissue.

Growth and development of the thymus is dependent on secretions from the anterior pituitary, presumably growth hormone. Diabetes mellitus is known to reduce immunological competence. These studies compare the effects of bovine growth hormone (bGH) and the growth factor produced by plerocercoid larvae of the tapeworm, Spirometra mansonoides, on metabolism of lymphoid tissue, thymus and spleen, in hypophysectomized rats made diabetic with a single intraperitoneal injection of alloxan. Whereas the control diabetic-hypophysectomized rats gradually lost weight throughout the experimental period, both bGH and plerocercoid infection caused significant weight gains during the experimental period. The diabetic-hypophysectomized rats treated with bGH had significantly heavier thymuses and spleens than controls. Plerocercoid infection also caused significant increases in thymus weights. Both bGH and plerocercoids stimulated the metabolic activity of thymocytes isolated from treated rats and tested for their ability to incorporate 3H-thymidine into DNA in vitro. Thus, these growth factors have similar effects on the lymphoid tissue of diabetic-hypophysectomized rats which are apparently independent of normal insulin levels. Whether this anabolic effect is direct or mediated by somatomedin remains to be determined.