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At least 19 recordsLinked to original sources

Comparative serological reactivity of Taenia crassiceps, Taenia solium and Taenia saginata metacestode neutral glycolipids to infection serum from Taenia crassiceps-infected mice.

A comparative survey was undertaken of the neutral fraction glycolipids from the metacestodes of 3 taeniid species, Taenia crassiceps, Taenia solium and Taenia saginata, to determine their chemical and serological staining patterns on separation by thin-layer chromatography. The orcinol-positive patterns of T. solium and T. saginata metacestodes exhibited a closer superficial resemblance to each other than to T. crassiceps or T. saginata adults. A comparison of component migration properties against standards of known structure indicated the main oligosaccharide chains to be mono-, di-, tri- and tetrasaccharides; however, in T. solium this was extended to at least a heptasaccharide. The multiple banding characteristic of each component is a consequence of lipid moiety heterogeneity. Serologically, the patterns of the 3 taeniid species neutral fraction glycolipids showed virtually the same immunological reactivity towards mouse normal serum, infection serum and a monospecific, polyclonal antibody directed against the trisaccharide component of T. crassiceps. The latter antibody was isolated from mouse infection serum by affinity chromatography on a column of glycolipid-bound octyl-Sepharose CL-4B. Immunochemically, the major common epitope expressed by the neutral fraction glycolipids of the 3 taeniid species is the same or very similar to the glycosphingolipid, neogalatriaosyl ceramide derived from the marine mollusc Turbo cornutus (Gal(beta 1-6) Gal(beta 1-6) Gal(beta 1-1)Cer). Host tissue neutral fraction glycolipids, porcine muscle and bovine muscle, as well as human spleen, were not immunoreactive.

Animals↗

Vaccination trials against Taiwan Taenia eggs in pigs injected with frozen oncospheres of Taiwan Taenia, Korea Taenia, T. saginata or T. solium.

When Small-Ear-Miniature pigs subcutaneously injected once with frozen oncospheres of Taiwan Taenia, Korea Taenia, T. saginata or T. solium emulsified with Freund's complete adjuvant (1.6 x 10(4)/0.4 ml) were challenged orally with 1.6 x 10(4) viable eggs of Taiwan Taenia 41 days later, they all showed strong resistance compared with pigs vaccinated with T. solium. Most pigs (5/8) of the former 3 groups harboured no cysticerci. The number of cysticerci was 5.5 +/- 9.1 (mean +/- S.D.), whereas pigs of the T. solium group and control group harboured 160 +/- 30.1 and 661 +/- 637.2 cysticerci, respectively. All cysticerci recovered from vaccinated pigs and most cysticerci in control pigs were degenerated or calcified at 36-55 days after oral egg challenge. These results strongly suggest that oncospheres of Taiwan Taenia and Korea Taenia are very similar to T. saginata in their immunogenicity in pigs.

Animals↗

A Taenia solium oncosphere protein homologous to host-protective Taenia ovis and Taenia saginata 18 kDa antigens.

A Taenia solium cDNA (TSOL-18) encoding a protein with close homology to host protective oncosphere antigens from Taenia ovis (To18) and Taenia saginata (TSA-18) is described here. TSOL-18 was cloned from mRNA obtained from hatched and activated oncospheres of T. solium. The high level of predicted amino acid sequence homology among TSOL-18 and other host protective taeniid antigens suggests that the protein expressed by TSOL-18 may be capable of being used as a vaccine against T. solium infection in the parasite's intermediate hosts.

Amino Acid Sequence↗

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.

Amino Acid Sequence↗

The location of Taenia pisiformis, Taenia ovis and Taenia hydatigena in the gut of the dog and its effect on net environmental contamination with ova.

Autopsy of dogs 56 days after infection with either T. pisiformis, T. ovis or T. hydatigena showed that these worms could be found attached at any point along the length of the small intestine, but were most commonly in the anterior half. The mean relaxed lengths of T. pisiformis, T. ovis and T. hydatigena were 107 cm, 156 cm and 177 cm respectively. Attached gravid proglottides contained a mean of 41 000 eggs each in T. pisiformis, 31 000 eggs in T. hydatigena and 95000 eggs in T. ovis, whereas proglottides free in the gut contained means of only 1370, 500 and 1400 eggs respectively; therefore, the majority of eggs were released into the gut before segments passed out into the faeces. It was shown that eggs of all 3 species of worms hatched and activated in the small intestine of the dog, especially in the anterior half. Eggs of T. pisiformis which had been passaged through the intestine of the dog and stored in the faeces for 5 days were poorly infective for rabbits compared with eggs only stored in faeces. It was concluded, therefore, that during taeniid infections of dogs the point of apolysis in the gut plays a significant role in determining environmental contamination with eggs. Puppies which had been fed 10000 T. ovis eggs daily for 6 weeks prior to infection with T. ovis cysticerci showed no difference in susceptibility to the infection when compared with untreated puppies.

Animals↗

Vaccination trials against Taenia solium eggs in pigs injected with frozen oncospheres of T. solium or Taenia saginata asiatica.

In this study, 12 Small-Ear-Miniature pigs aged 142 to 185 days were used to determine whether pigs injected with nonviable oncospheres of Taenia solium or Taenia saginata asiatica can become resistant to the challenge of viable eggs of T. solium. The 12 pigs were equally divided into 4 groups: 3 experimental groups in which each pig was injected subcutaneously with a mixture of 0.2 mL complete Freund's adjuvant and 10(4)/0.2 mL nonviable Taiwan/Asian Taenia, Indonesia Taenia, or T. solium oncospheres, and 1 control group in which each pig was injected subcutaneously with 0.2 mL phosphate buffer solution and 0.2 mL complete Freund's adjuvant. Each pig was orally inoculated with 10000 viable T. solium eggs 1 month later. The infection rates were 100% (2/2), 100% (3/3), 33% (1/3), and 100% (3/3) and cysticerci recovery rates were 1.3% (254/20000), 1.2% (371/30000), 0.01% (4/30000), and 8.6% (2,577/30000), respectively. Except for the location of 72 cysticerci located in the viscera, 3134 cysticerci were recovered from the muscles. In the experimental groups, 4 cysticerci recovered were viable and the remaining 625 were either calcified or degenerated. However, 2567 cysticerci recovered from the control group remained viable and only 10 were calcified or degenerated. The results indicate that in addition to the vaccine of T. solium, those of Taiwan Taenia and Indonesia Taenia can also induce high-crossing immunologic reactions against T. solium infection.

Animals↗

Cross protection against Taenia taeniaeformis in rats vaccinated with non-viable oncospheres of Asian Taenia or T. saginata.

It was determined to examine whether rats injected with non-viable oncospheres of Asian Taenia or Taenia saginata became resistant to challenge infection with eggs of Taenia taeniaeformis, since (a) metacestodes of Asian Taenia and T. taeniaeformis develop in the liver of pigs and rats, respectively, and (b) Asian Taenia and T. saginata have human origins. Rats injected intravenously or subcutaneously with complete Freund's adjuvant with non-viable oncospheres of Asian Taenia showed statistically significant resistance to challenge infection with eggs of T. taeniaeformis, whereas those injected with non-viable oncospheres of T. saginata did not show any resistance.

Animals↗

Differential diagnosis of Taenia saginata and Taenia solium with DNA probes.

A size selected genomic DNA library was constructed using DNA extracted from Taenia saginata. The DNA was digested using the restriction enzyme EcoR1 under star conditions and the 2-4 kbase fraction, selected following sucrose density-gradient separation, was cloned in the bacteriophage lambda gt 10. A panel of cestode DNAs including Taenia saginata, Taenia solium, Taenia taeniaeformis, Taenia crassiceps, Echinococcus granulosus and DNAs of bovine, porcine and human origin were used in conjunction with hybridization analysis to identify two recombinant bacteriophages. The first probe, designated HDP1, reacted specifically with T. saginata DNA. The second, designated HDP2, reacted with DNA from both T. saginata and T. solium but not the other DNA samples and thus provided a general reagent for positive identification of fragments of Taenia spp. proglottides of human faecal origin. If used in conjunction the two DNA probes allow positive identification of T. saginata. In the clinical situation it is important to be able to distinguish T. saginata and T. solium infections and DNA probes such as these may be useful in such differentiation.

Animals↗

Isolation and characterization of species-specific DNA probes from Taenia solium and Taenia saginata and their use in an egg detection assay.

Cysticercosis results from ingestion of the eggs of the tapeworm Taenia solium. Reduction of the incidence of human and swine cysticercosis requires identification and treatment of individuals who carry the adult tapeworm. T. solium and Taenia saginata eggs cannot be differentiated on the basis of morphology; thus, in order to improve existing methods for the diagnosis of taeniasis, we have developed highly sensitive, species-specific DNA probes which differentiate T. solium and T. saginata. Recombinant clones containing repetitive DNA sequences which hybridize specifically with genomic DNAs from either species were isolated and characterized. T. solium-specific DNA sequences contained complete and truncated forms of a tandemly repeated 158-bp DNA sequence. An unrelated T. saginata DNA sequence was also characterized and shown to encode a portion of the mitochondrial cytochrome c oxidase I gene. T. solium- and T. saginata-specific DNA probes did not hybridize in dot blot assays either with genomic DNA from the platyhelminths Taenia hydatigena, Taenia pisiformis, Taenia taeniaeformis, Echinococcus granulosus, and Schistosoma mansoni or with genomic DNA from other eukaryotes, including Saccharomyces cerevisiae, Candida albicans, Cryptosporidium parvum, Entamoeba histolytica, Trypanosoma gambiense, Trypanosoma brucei, and Giardia lamblia, Caenorhabditis elegans, and human DNA. By using these T. solium and T. saginata DNA probes, a rapid, highly sensitive and specific dot blot assay for the detection of T. solium eggs was developed.

Animals↗

Taenia saginata and Taenia solium: reciprocal models.

Taenia solium and Taenia saginata are of such close taxonomic relationship that each can be regarded as a model for the other. In these particular species the only available hosts are either humans or large domesticated animals. This has imposed severe safety and/or economic restrictions on the extent of the experimental work which could be attempted. Furthermore, there is a limit to the relevance of work with less closely related species such as Taenia ovis, Taenia taeniaeformis and Taenia pisiformis with their differing host species, larval forms and locations within the intermediate host tissue. However, the application of both monoclonal antibody based and modern molecular biological techniques to the T. solium and T. saginata systems does much to overcome or circumvent some of the problems. Thus advances made in the analysis, diagnosis or immuno-prophylaxis of one of these species are at least potentially both of direct and immediate or indirect benefit to the work on the other species.

Animals↗

Prolactin in the Cestodes, Taenia solium and Taenia hydatigena: an immunocytochemical study.

The demonstration of prolactin in cestodes, Taenia solium and Taenia hydatigena, was investigated by using immunocytochemical method. PRL immunoreactivity was widely distributed in the CNS and PNS in the worms. In the scolex PRL-IR perikarya occurred in the cerebral ganglia, around the basic area of the sucker and the rostral border region between the rostellum and the suckers with strong immunoreaction, distinctly in Taenia solium. A number of PRL-IR nerve fibres were observed in the main nerve cords, and a few fibres in the transverse nerve commissure. The holdfast musculature of the scolex was innervated by the PRL-IR fibres. A large number of PRL positive cells with processes and nerve plexuses were seen in the ootype/Mehlis' gland complex, oviduct, the duct of uterum, seminal receptacle and its associated duct, conspicuously in Taenia hydatigena. PRL-IR was evident in the wall of vas efferens of tests and vas deferens. A few PRL positive cells occurred in the medullary parenchyma amongst testes and sent their varicose processes to terminate to the testes. On the wall of the main excretory duct a few PRL-IR cells and fibres were seen.

Animals↗

Specific antibody responses to Taenia hydatigena, Taenia pisiformis and Echinococcus granulosus infection in dogs.

Groups of dogs reared free of both nematodes and cestodes were infected with Taenia hydatigena, Taenia pisiformis or Echinococcus granulosus. After infections with the Taenia spp became patent, dogs were purged to remove the worms. They were later reinfected and the second infections again removed by purging after patency. A group of 3 uninfected worm free dogs was kept as age-matched controls. The dogs were bled at intervals of 5 days and their serums tested for antibodies using the enzyme-linked immunosorbent assay (ELISA) with excretory/secretory (ES) antigens collected during in vitro incubation of evaginated scoleces (scolex ES antigen) and oncosphere antigens. Antibodies to scolex ES antigen were detected by 3 weeks after infection with each cestode species whereas antibodies to oncosphere antigen were not detected until about one week after eggs were found in the faeces of the infected dogs. Antibody responses to both oncosphere and scolex ES antigens decreased rapidly following removal of the worms by purging. Uninfected control dogs were invariably negative to both oncospheral and scolex ES antigens. There were cross-reactions between the serums from dogs infected with T. pisiformis and T. hydatigena when tested with scolex ES antigens, but oncospheral antigens showed a high degree of species specificity. Scolex ES antigens from E. granulosus were compared with those prepared from T. hydatigena and T. pisiformis for their ability to discriminate between antibodies in serums collected from dogs 31 and 32 days after infection with 100,000 protoscoleces of E. granulosus or dogs infected with Taenia spp.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Protective immunity against Taenia crassiceps murine cysticercosis induced by DNA vaccination with a Taenia saginata tegument antigen.

This study investigated the protective capacity of the recombinant Taenia saginata Tso18 antigen administered as a DNA vaccine in the Taenia crassiceps murine model of cysticercosis. This Tso18 DNA sequence, isolated from a T. saginata oncosphere cDNA library, has homologies with Taenia solium and Echinococcus sp. It was cloned in the pcDNA3.1 plasmid and injected once intramuscularly into mice. Compared to saline-vaccinated control mice, immunization reduced the parasite burden by 57.3-81.4%, while lower levels of non-specific protection were induced in control mice injected with the plasmid pcDNA3.1 (18.8-33.1%) or a plasmid with irrelevant construct, pcDNA3.1/3D15 (33.4-38.8%). Importantly, significant levels of protection were observed between the pcDNA3.1/Tso18 plasmid and pcDNA3.1/3D15 plasmid immunized mice. Mice immunized with pTso18 synthesized low levels of, primarily IgG1 sub-class, antibodies. These antibodies were shown to recognize a 66 kDa antigen fraction of T. crassiceps and T. solium. Splenocytes enriched in both CD4+CD8- and CD4-CD8+ T cells from these vaccinated mice proliferated in vitro when exposed to antigens from both T. solium and T. crassiceps cestodes. Immunolocalization studies revealed the Tso18 antigen in oncospheres of T. saginata and T. solium, in the adult tapeworm and in the tegument of T. solium cysticerci. The protective capacity of this antigen and its extensive distribution in different stages, species and genera of cestodes points to the potential of Tso18 antigen for the possible design of a vaccine against cestodes.

Animals↗

Alternative splicing and sequence diversity of transcripts from the oncosphere stage of Taenia solium with homology to the 45W antigen of Taenia ovis.

Genes and transcripts which show homology to the host-protective 45W antigen of Taenia ovis have been cloned from the human parasite Taenia solium. The T. solium genes cloned in this study (TSO45) show conserved genomic structural features which are also features of the T. ovis 45W gene family. The TSO45 genes consist of a four exon and three intron structure. Eight TSO45 transcripts, encoded by at least five genes, were cloned from T. solium oncospheres and comparison of their DNA sequence indicates that some transcripts have arisen by alternative splicing, the first demonstration of exon inclusion/exon skipping in cestodes. Alternative splicing occurred with respect to both exons II and III with three splice variants identified from the TSO45-1 gene and two splice variants from TSO45-5. The proteins encoded by this family of genes contain putative N-linked glycosylation sites, an amino terminal secretory signal, a hydrophobic carboxy terminal sequence characteristic of GPI-anchored proteins and fibronectin type III motifs. These features are common to their T. ovis and Taenia saginata homologues. The similarities of the TSO45 genes cloned in this study with genes encoding host-protective antigens of T. ovis and T. saginata indicates that the encoded T. solium proteins are quite possibly antigenic and have potential use as a vaccine to prevent T. solium infection in the parasite's intermediate host. In this respect, the generation of sequence diversity and hence potential antigenic diversity through alternative splicing of TSO45 genes may have implications for the use of these proteins in vaccines against T. solium cysticercosis.

Alternative Splicing↗

Specific Taenia crassiceps and Taenia solium antigenic peptides for neurocysticercosis immunodiagnosis using serum samples.

Neurocysticercosis (NC), i.e., the presence of the larval form of Taenia solium in tissues, is the most frequent and severe infection involving the central nervous system. Paired serum and cerebrospinal fluid (CSF) samples from patients with NC, CSF and serum samples from a control group, and serum samples from patients with other parasitoses were studied by enzyme-linked immunosorbent assay (ELISA) and by immunoblotting with Taenia crassiceps vesicular fluid antigen (Tcra) and Taenia solium total saline antigen (Tso) for the detection of immunoglobulin G antibodies. ELISAs carried out with the Tso and Tcra antigens showed 94.1 and 95.6% sensitivities, respectively, for the detection of antibodies in CSF and 70.6% and 91.2% sensitivities, respectively, for the detection of antibodies in serum, with 100% specificity for the detection of antibodies in CSF and 80% specificity for the detection of antibodies in serum for both antigens. On the basis of the reactivities of the peptides in the samples analyzed, the peptides of </=23, 39, 85 to 77, and 97 kDa were found to be Tso specific by immunoblotting and the peptides of </=62, 74, 109, 121, and 131 kDa were found to be Tcra specific. Tests with Tcra extract had higher sensitivities and more homogeneous results and permitted us to obtain the parasites easily. We suggest the use of Tcra ELISA for the study of serum and confirmation of the results for sera positive by an immunoblotting analysis in which specific peptides (e.g., peptides of 19 to 13 kDa) are detected.

Antibodies, Helminth↗