Praziquantel treatment of porcine brain and muscleTaenia solium cysticercosis

PorcineTaenia solium cysticercosis, recognized as a model of the human disease, was used to analyze the effect of the anthelminthic drug praziquantel on hosts and parasites. The drug (50 mg/kg daily) was given over 15 days in the feed of 13 cysticercotic and 9 control pigs. Changes in the number, size and appearance of brain parasites were seen by computerized tomography immediately after the last dose of praziquantel, although not all cysticerci had disappeared by day 47 following the end of the treatment. Muscle parasites became small and hyperdense shortly after treatment and disappeared from tomographic images afterwards. No alterations were found in EEGs or in brain-stem auditory and somatosensory evoked potentials. Muscle cysticerci showed increasing degrees of degeneration with time after treatment, and an augmented inflammatory reaction was concomitantly observed. In contrast, more heterogeneous results were obtained in parasites lodged in the brain, since viable cysts and less intense inflammatory reactions were found in the brain at different times after treatment. Physiological evaluation of the parasites showed that evagination was inhibited immediately after treatment and that oxygen consumption decreased with time. The results of this investigation suggest that praziquantel damages cysticerci and that the inflammatory reaction destroys and eliminates them.     

Towards a Taenia solium cysticercosis vaccine: an epitope shared by Taenia crassiceps and Taenia solium protects mice against experimental cysticercosis

The Taenia crassiceps recombinant antigen KETc7 has been shown to be effective as a vaccine against experimental murine cysticercosis, a laboratory model used to test potentially promising molecules against porcine Taenia solium cysticercosis. Based on the deduced amino acid sequence of this proline-rich polypeptide, three fragments, GK-1, GK-2, and GK-3, were chemically synthesized in linear form. Of the three peptides, only GK-1 induced sterile protection against T. crassiceps cysticercosis in 40 to 70% of BALB/cAnN male mice. GK-1 is an 18-amino-acid peptide which contains at least one B-cell epitope, as demonstrated by its ability to induce an antibody response to the peptide and T. crassiceps antigen without need of a carrier protein. Immunofluorescence studies revealed that anti-GK1 antibodies strongly react with the native protein in the tegument of T. crassiceps and also with anatomical structures of T. solium eggs, oncospheres, cysticercus, and tapeworm. GK-1 also contains at least one T-cell epitope, capable of stimulating the proliferation of CD8(+) and to a lower extent CD4(+) T cells primed either with the free peptide or T. crassiceps total antigen. The supernatant of the stimulated cells contained high levels of gamma interferon and low levels of interleukin-4. Similar results were obtained with T cells tested for intracellular cytokine production, an indication of the peptide's capacity to induce an inflammatory response. The remarkable protection induced by GK-1 immunization, its physicochemical properties, and its presence in all developmental stages of T. solium point to this synthetic peptide as a strong candidate in the construction of a synthetic vaccine against T. solium pig cysticercosis.     

Toward development of a Taenia solium paramyosin-based vaccine against porcine cysticercosis

Taenia solium paramyosin (TPmy) is a prominent 100 kDa antigen in human and porcine cysticercosis. TPmy is an alpha-helical coiled coil protein present in muscle and tegumentary structures of T. solium cysticerci. TPmy has the property of binding C1q resulting in inhibition of the complement cascade. TPmy probably binds C1q through its collagen-like domains and could be involved in a parasite strategy to modulate host immune response. Humoral immune response against TPmy is prefrentially directed against carboxyl terminal end in humans and mice, whereas amino terminal end of TPmy preferentially induces a Th1-related cellular immune response. Protection studies in murine model of cysticercosis showed that the amino terminal end fragment of TPmy induces approximately 60% protection against an i.p. challenge with Taenia crassiceps cysts when mice are immunized with recombinant fragments of TPmy. Initial protection studies using genetic immunization showed that amino terminal end fragment of TPmy cloned into a plasmid expression vector with a cytomegalovirus promoter, together with IL-12-expressing plasmids induced 79% protection, suggesting that this kind of TPmy-immunization might result in development of a cost-effective vaccine against cysticercosis.     

An ocular cysticercosis case: Caused by Asian genotype of Taenia solium

An ocular cysticercosis case of a 42-year-old male, who presented with anterior uveitis is being reported. Microscopical examination of the cyst revealed presence of only one hooklet suggestive of T. solium cysticercus. Mitochondrial DNA analysis confirmed it to be T. solium cysticercus of Asian genotype. This is the first report on molecular typing of cysticercus isolate from ocular cysticercosis patient in India. The study suggests that the molecular analysis of cox1 gene may be a useful diagnostic tool in cases where microscopic examination is not confirmatory.     

Seroepidemiological observation of Taenia solium cysticercosis in epileptic patients in Korea.

Prevalence survey of neurocysticercosis was made in a mixed epilepsy patients of Changmi Club in Korea. From February 1987 to July 1990, a total of 2,667 randomly selected patients at 27 local centers was tested for their serum levels of anti-Cysticercus antibody (IgG) by enzyme-linked immunosorbent assay. Positive rate of the antibody was 4.0% in the examined patients. The standardized antibody positive rate by provincial population was 3.1%. The rate was the highest in patients living in Cheju Do (8.4%). The patient age brackets of 0 approximately 9 years and over 50-year showed higher positive rates of the antibody. In 750 normal persons who checked up routine physical examination, the antibody positive rate was 2.1% (standardized rate was 1.8%). These seroepidemiological data disclosed for the first time the prevalence of cysticercosis in epileptic patients and in population.     

Characterization and cloning of T24, a Taenia solium antigen diagnostic for cysticercosis

The third and final diagnostic antigen of the lentil lectin purified glycoproteins (LLGP) extracted from the larval stage of Taenia solium has been characterized, cloned, and expressed. T24 is an integral membrane protein that belongs to the tetraspanin superfamily. It migrates at a position corresponding to 24-kDa and as a homodimer at 42-kDa. Antibodies from cysticercosis patients recognize secondary structure epitopes that are dependent upon correctly formed disulfide bonds. A portion of T24, the large, extracellular loop domain, was expressed in an immunologically reactive form in insect cells. When tested in a Western blot assay with a large battery of serum samples, this protein, T24H, has a sensitivity of 94% (101/107), for detecting cases of cysticercosis with two or more viable cysts, and a specificity of 98% (284/290). The identification and expression of T24H sets the stage for the development of an ELISA suitable for testing single samples and for large-scale serosurveys that is not dependent upon the isolation and purification of antigens from parasite materials.     

Characterization and cloning of GP50, a Taenia solium antigen diagnostic for cysticercosis

GP50, a Taenia solium protein diagnostic for cysticercosis has been cloned, sequenced, and characterized. GP50 is one diagnostic component of the lentil lectin purified glycoprotein (LLGP) antigens that have been used for antibody-based diagnosis of cysticercosis in a Western blot assay for nearly 15 years. GP50 is a glycosylated and GPI-anchored membrane protein. The native protein migrates at 50kDa, but the predicted molecular weight of the mature protein is 28.9. Antigenically active recombinant GP50 has been expressed in a baculovirus expression system. The antigenic activity of both the native and recombinant proteins is dependent upon the correct formation of disulfide bonds. GP50, purified from cysticerci, has two homologs expressed in the adult worm, TSES33 and TSES38. Both are diagnostic for taeniasis. In spite of the amino acid similarities between GP50 and the TSES proteins, each appears to be a stage-specific antigen. A preliminary evaluation of recombinant GP50 in a Western blot assay showed 100% specificity for cysticercosis and 90% sensitivity for cysticercosis positive serum samples reactive with the GP50 component of LLGP.     

Comparative evaluation of purified Taenia solium glycoproteins and crude metacestode extracts by immunoblotting for the serodiagnosis of human T. solium cysticercosis.

A lentil-lectin purified glycoprotein (LL-Gp) and a crude saline extract of Taenia solium metacestodes were compared for the immunodiagnosis of human cysticercosis by immunoblotting. The LL-Gp preparation was 95% sensitive for antibodies against a range of seven antigens with molecular masses of 50 to 13 kDa, whereas the sensitivity of the crude saline extract for the detection of antibodies against two major polypeptide molecules (26 and 8 kDa) was 91%. Specificity was 100% with both sets of diagnostic antigens. Affinity-purified antibodies against the 26-kDa molecule from the crude saline extract recognized the 24-kDa diagnostic region in the LL-Gp-purified extract and vice versa, suggesting that the antigens had common epitopes recognized by cysticercotic sera. In addition, in a preliminary community study of 115 randomly selected people from Bali (Indonesia), seroprevalence by immunoblot assay varied from 7.8% (with the crude saline antigen extract) to 9.6% (with the LL-Gp-purified extract). The results of this study demonstrate that both antigenic preparations are applicable for the immunodiagnosis of T. solium cysticercosis. The crude T. solium metacestode antigen extract was as specific as the purified LL-Gp T. solium metacestode extract and simpler to produce but slightly less sensitive.     

Genetic vaccination against murine cysticercosis by using a plasmid vector carrying Taenia solium paramyosin

A plasmid vector carrying the immunoprotective amino-terminal fragment of Taenia solium paramyosin (VW2-1) was designed for genetic vaccination studies. Mice that were genetically immunized with VW2-1 and challenged by intraperitoneal inoculation of Taenia crassiceps cysticerci showed 43 to 48% reductions in the parasite burden, values which were similar to values obtained previously when the recombinant protein was used.     

Immunodiagnosis of human cysticercosis (Taenia solium) with antigens purified by monoclonal antibodies.

Monoclonal antibodies were generated from mice immunized with scolex protein antigen of Cysticercus cellulosae. Three monoclonal antibodies specific for cysticercal antigens, which did not show any cross-reactivity with Taenia solium or Taenia saginata antigens, were selected. Each monoclonal antibody coupled to Sepharose could purify one antigen, which appeared as a single band on polyacrylamide gel electrophoresis. When antigens purified by monoclonal antibodies were used to detect antibody in serum samples taken from patients with cysticercosis, taeniasis, and other parasitic infections in an enzyme-linked immunosorbent assay, cross-reactivity was observed until a serum dilution of 1:128 was reached. Since serum samples from unexposed subjects showed positive reactions until a dilution of 1:64 was reached, we chose a discriminative dilution (1:128) above which no cross-reaction was observed. The percent positive serum samples from cysticercosis patients was 100% by the enzyme-linked immunosorbent assay with any of the antigens purified by monoclonal antibodies.     

Serological diagnosis of human cysticercosis by use of recombinant antigens from Taenia solium cysticerci.

A Taenia solium metacestode cDNA expression library in the lambda ZAPII vector was screened with pooled sera from patients with neurocysticercosis. Sixty primary clones were identified and shown to belong to two classes. The clones NC-3 and NC-9 did not reveal any significant homologies to sequences deposited in the databases and were further characterized. Both recombinant antigens were expressed as glutathione S-transferase fusion proteins and applied for serological diagnosis of human cysticercosis. An enzyme-linked immunosorbent assay was established and evaluated with 27 serum samples of La Réunion and Madagascar patients with cysticercosis. Diagnosis in these patients was established with radiological and serological procedures. For antigen NC-3 a sensitivity of 96.3% and a specificity of 91.5% for the serodiagnosis were achieved. In contrast, the sensitivity of antigen NC-9 was only 33.3%.     

A review of the control of clonorchiasis sinensis and Taenia solium taeniasis/cysticercosis in China

Clonorchiasis sinensis and Taenia solium taeniasis/cysticercosis are major foodborne parasitoses. Clonorchiasis sinensis is actively transmitted in some areas of China, Korea, Russia, Vietnam, etc. Currently, it is estimated that more than 200 million people are at risk of infection, 15–20 million people are infected, and 1.5–2 million show symptoms or complications. In China, it is relatively heavily transmitted in Zhujiang River Delta, including Hong Kong and Macao, and Northeast China, where many Korean people live. The transmission is related to the unhealthy habits of residents who like to have raw fish or half-raw fish. The infection of Clonorchis sinensis could result in serious liver and biliary system damages, and chronic cases may induce liver and bile duct cancers. T. solium taeniasis/cysticercosis is distributed around the world except the areas where the residents have a taboo against pork for religious reasons. Recent years, the urban inhabitants infected with T. solium/Cysticercus are increasing in China. T. solium results in intestinal diseases, and cysticercosis is a very serious disease, especially nervous system cysticercosis. Its symptoms include headache, epilepsy, sudden death, etc. Health education and health promotion, environmental reconstruction, and chemotherapy are the main control measures for these diseases. Through several decades of efforts in China, the achievements of control of clonorchiasis and T. solium taeniasis/cysticercosis are great. For example, in one of the main clonorchiasis-endemic provinces, Shandong Province, clonorchiasis has been controlled. In 31?T. solium taeniasis/cysticercosis-endemic counties of Henan Province, through a 6-year control program, the decline rates of T. solium taeniasis and cysticercosis were 90.8 and 96.8?%, respectively. This paper reviews the researches on the control of clonorchiasis and T. solium taeniasis/cysticercosis in China past decades so as to provide references for other countries where these diseases are endemic to improve the control or elimination of clonorchiasis and T. solium taeniasis/cysticercosis.     

Characterization and protective potential of the immune response to Taenia solium paramyosin in a murine model of cysticercosis

Paramyosin has been proposed as a vaccine candidate in schistosomiasis and filariasis. However, limited information is available about its protective potential against cysticercosis and the immune response it induces. Immunization of mice with recombinant full-length paramyosin of Taenia solium (TPmy) results in about a 52% reduction in parasite burden after a subsequent challenge by intraperitoneal inoculation of Taenia crassiceps cysticerci. Immunization assays using recombinant fragments of TPmy, corresponding approximately to thirds on the amino, central, or carboxyl regions, suggest that protective epitopes are located mostly in the amino-end third. Proliferation assays using T cells obtained from mice immunized with the full-length recombinant TPmy also showed a preferential response to the amino-terminal fragment. In contrast, antibodies in the sera from these mice predominantly recognize epitopes located in the carboxyl-terminal fragment, being the immunoglobulin G1 subclass, the predominant antibody isotype. Characterization of the cellular immune response induced against the protective amino-terminal fragment reveals production of gamma interferon and interleukin-2, but not interleukin-4, suggesting a Th1-like profile.     

Taenia solium metacestode preparation in rural areas of sub-Saharan Africa: a source for diagnosis and research on cysticercosis

BackgroundTaenia solium metacestodes/cysts obtained from pig carcasses constitute a primary source for diagnostic tools used for the detection of human cysticercosis. Data on T. solium cyst preparation in Africa is still scarce but required to establish independent reference laboratories.ObjectivesThe aim of the present study is a) to present the likely yield of T. solium cyst material by the use of two different preparation methods in the field and b) to investigate its suitability for immunodiagnosis of human cysticercosis.MethodsIn Zambia, Uganda and Tanzania 670 pigs were screened for T. solium infection. Cysts were prepared by ‘shaking method’ and ‘washing method’. Generated crude antigens were applied in a standard western blot assay.Results46 out of 670 pigs (6.9%) were found positive for T. solium (Zambia: 12/367, 3.3%; Uganda: 11/217, 5.1%; Tanzania 23/86, 26.7%). Mean values of 77.7 ml whole cysts, 61.8 ml scolices/membranes and 10.9 ml cyst fluid were obtained per pig. Suitability of collected material for the use as crude antigen and molecular diagnostic techniques was demonstrated.ConclusionThis study clearly shows that T. solium cyst preparation in African settings by simple field methods constitutes an effective way to obtain high quality material as source for diagnostic tools and research purposes.     

Praziquantel in human hydatidosis. Evaluation by preoperative treatment

The efficacy of praziquantel has been studied in human hydatic disease due to E. granulosus, using parasitological and pharmacological criteria of improvement. This evaluation uses a prospective therapeutic trial in 15 patients with one or several hydatic cysts in different sites. Before surgery, nine of these received daily 75 mg/kg of praziquantel in 2 courses of 10 days each. The other six patients are considered as controls. The protoscolices vitality is determined by direct optic microscopy and by intraperitoneal mouse inoculation. According to the results of optic microscopy, praziquantel sterilizes hydatic cysts: 19 sterilized cysts out of 26 coming from treated patients, and 4 out of 11 in control group. This effect seems to be emphasized in hepatic localization. Nevertheless, according to the results of mouse inoculation, praziquantel does not significantly reduce the pathogenicity of inoculated proscolices and germinal layer: 11 mice out of 39 are healthy in the treated group, and 5 out of 15 in controls. Moreover, the determination with a fluorimetric method has not detected praziquantel in the hydatid liquid issued from treated patients. The drug does not pass through the cyst wall, and so, cannot have a scolicidal activity. Praziquantel cannot be considered as a medical treatment in human hydatidosis.     

Adjuvant effects of bacillus Calmette-Guerin DNA or CpG-oligonucleotide in the immune response to Taenia solium cysticercosis vaccine in porcine

The immune stimulation properties of CpG-oligonucleotides (CpG-ODN) containing a central unmethylated CpG motif could be useful for vaccination against parasite infection. However, the high cost of synthetic CpG-ODN has limited its use in veterinary vaccines. In this study, we investigated whether genomic DNA derived from Mycobacterium bovis bacillus Calmette-Guerin (BCG-DNA) could be used as an effective adjuvant to enhance the immunogenicity and the protective capacity of recombinant cC1 antigen (rcC1) against pig cysticercosis. Pigs were vaccinated with rcC1 plus CpG-containing DNA adjuvants (BCG-DNA or CpG-ODN) or rcC1 alone. Immunization with rcC1 alone induced a Th1-biased response, whereas coadministration of rcC1 with BCG-DNA or CpG-ODN increased levels of IgG2, IFN-gamma, percentage of CD8+ and specific proliferation of peripheral blood mononuclear cells. Four weeks after the last immunization, pigs were infected with Taenia solium eggs. A high level of protection (81%) was induced by rcC1 immunization that was not significantly increased by the CpG-containing DNA. These data indicate that coadministration of rcC1 plus BCG-DNA or CpG-ODN significantly enhanced Th1 response but did not improve the level of the protection induced.