RESUMO
The larval stages of the cestode parasites belonging to the genus Echinococcus grow within internal organs of humans and a range of animal species. The resulting diseases, collectively termed echinococcoses, include major neglected tropical diseases of humans and livestock. Echinococcus larvae are outwardly protected by the laminated layer (LL), an acellular structure that is unique to this genus. The LL is based on a fibrillar meshwork made up of mucins, which are decorated by galactose-rich O-glycans. In addition, in the species cluster termed E. granulosus sensu lato, the LL features nano-deposits of the calcium salt of myo-inositol hexakisphosphate (Insp6). The main purpose of our article is to update the immunobiology of the LL. Major recent advances in this area are (i) the demonstration of LL "debris" at the infection site and draining lymph nodes, (ii) the characterization of the decoy activity of calcium Insp6 with respect to complement, (iii) the evidence that the LL mucin carbohydrates interact specifically with a lectin receptor expressed in Kupffer cells (Clec4F), and (iv) the characterization of what appear to be receptor-independent effects of LL particles on dendritic cells and macrophages. Much information is missing on the immunology of this intriguing structure: we discuss gaps in knowledge and propose possible avenues for research.
Assuntos
Equinococose , Echinococcus granulosus , Echinococcus , Animais , Cálcio , Equinococose/parasitologia , Echinococcus/imunologia , Echinococcus granulosus/química , Echinococcus granulosus/imunologia , MucinasRESUMO
Cystic echinococcosis is a parasitic infection of worldwide distribution, which, despite causing significant loss of health and money, is still a neglected disease. The present study was performed to determine the prevalence of bovine hydatid disease at Research Centre for the Conservation of Sahiwal Cattle, Jahangirabad, Khanewal, Pakistan. Five hundred bovine serum samples were tested for the detection of bovine Echinococcus antibodies (IgG), using the ELISA kits. Antibodies of bovine Echinococcus were detected in 24.2% cattle. Female cattle showed higher disease prevalence (33.2%) compared to (6.02%) in male cattle. There was positive association between sex of cattle and prevalence (P<0.05). Positive correlation between disease prevalence and age was detected. Younger animals (<3 years old) had lower prevalence value of disease than to older animals (> 3 years old). It is concluded that there is high degree of exposure of cattle to Echinococcus at Research Centre for Conservation of Sahiwal Cattle, Khanewal, Punjab. Measures should be taken to reduce risk of disease to avoid its spread to humans as well as great degree of economic losses.(AU)
A equinococose cística é uma infecção parasitária de distribuição mundial que, apesar de causar perda significativa de saúde e dinheiro, ainda é uma doença negligenciada. O presente estudo foi realizado para determinar a prevalência da doença hidatídea bovina no Centro de Pesquisa para Conservação do Gado Sahiwal, Jahangirabad, Khanewal, Paquistão. Quinhentas amostras de soro bovino foram testadas para a detecção de anticorpos anti Echinococcus de bovinos (IgG), utilizando os kits ELISA. Anticorpos de contra Echinococcus bovino foram detectados em 24,2% dos bovinos. As fêmeas apresentaram maior prevalência de doenças (33,2%) em comparação com (6,02%) nos machos. Existe associação positiva entre sexo do gado e prevalência (P<0,05). Foi detectada correlação positiva entre a prevalência da doença e a idade. Animais mais jovens (<3 anos) apresentaram menor valor de prevalência da doença do que animais mais velhos (>3 anos). Conclui-se que existe um alto grau de exposição do gado ao Echinococcus no Centro de Pesquisa para Conservação do Gado Sahiwal, Khanewal, Punjab. Devem ser tomadas medidas para reduzir o risco de doenças e evitar sua propagação para os seres humanos, além de um grande grau de perdas econômicas.(AU)
Assuntos
Animais , Bovinos , Echinococcus/imunologia , Equinococose/epidemiologia , Equinococose/veterinária , Fatores Sexuais , Estudos Soroepidemiológicos , Paquistão , Ensaio de Imunoadsorção Enzimática/veterináriaRESUMO
Granulomas are responses to persistent nonliving bodies or pathogens, centrally featuring specialized macrophage forms called epithelioid and multinucleated giant cells. The larval stages of the cestode parasites of the Taeniidae family (Taenia, Echinococcus) develop for years in fixed tissue sites in mammals. In consequence, they are targets of granulomatous responses. The information on tissue responses to larval taeniids is fragmented among host and parasite species and scattered over many decades. We attempt to draw an integrated picture of these responses in solid tissues. The intensity of inflammation around live parasites spans a spectrum from minimal to high, parasite vitality correlating with low inflammation. The low end of the inflammatory spectrum features collagen capsules proximal to the parasites and moderate distal infiltration. The middle of the spectrum is dominated by classical granulomatous responses, whereas the high end features massive eosinophil invasions. Across the range of parasite species, much observational evidence suggests that eosinophils are highly effective at killing larval taeniids in solid tissues, before and during chronic granulomatous responses. The evidence available also suggests that these parasites are adapted to inhibit host granulomatous responses, in part through the exacerbation of host regulatory mechanisms including regulatory T cells and TGF-ß.
Assuntos
Equinococose/patologia , Echinococcus/imunologia , Granuloma/parasitologia , Larva/imunologia , Taenia/imunologia , Teníase/patologia , Animais , Equinococose/parasitologia , Eosinófilos/imunologia , Granuloma/imunologia , Inflamação/parasitologia , Macrófagos/imunologia , Mamíferos/parasitologia , Linfócitos T Reguladores/imunologia , Teníase/parasitologiaRESUMO
The larva of cestodes belonging to the Echinococcus granulosus sensu lato (s.l.) complex causes cystic echinococcosis (CE). It is a globally distributed zoonosis with significant economic and public health impact. The most immunogenic and specific Echinococcus-genus antigen for human CE diagnosis is antigen B (AgB), an abundant lipoprotein of the hydatid cyst fluid (HF). The AgB protein moiety (apolipoprotein) is encoded by five genes (AgB1-AgB5), which generate mature 8 kDa proteins (AgB8/1-AgB8/5). These genes seem to be differentially expressed among Echinococcus species. Since AgB immunogenicity lies on its protein moiety, differences in AgB expression within E. granulosus s.l. complex might have diagnostic and epidemiological relevance for discriminating the contribution of distinct species to human CE. Interestingly, AgB2 was proposed as a pseudogene in E. canadensis, which is the second most common cause of human CE, but proteomic studies for verifying it have not been performed yet. Herein, we analysed the protein and lipid composition of AgB obtained from fertile HF of swine origin (E. canadensis G7 genotype). AgB apolipoproteins were identified and quantified using mass spectrometry tools. Results showed that AgB8/1 was the major protein component, representing 71% of total AgB apolipoproteins, followed by AgB8/4 (15.5%), AgB8/3 (13.2%) and AgB8/5 (0.3%). AgB8/2 was not detected. As a methodological control, a parallel analysis detected all AgB apolipoproteins in bovine fertile HF (G1/3/5 genotypes). Overall, E. canadensis AgB comprised mostly AgB8/1 together with a heterogeneous mixture of lipids, and AgB8/2 was not detected despite using high sensitivity proteomic techniques. This endorses genomic data supporting that AgB2 behaves as a pseudogene in G7 genotype. Since recombinant AgB8/2 has been found to be diagnostically valuable for human CE, our findings indicate that its use as antigen in immunoassays could contribute to false negative results in areas where E. canadensis circulates. Furthermore, the presence of anti-AgB8/2 antibodies in serum may represent a useful parameter to rule out E. canadensis infection when human CE is diagnosed.
Assuntos
Equinococose/veterinária , Echinococcus/química , Proteínas de Helminto/química , Lipoproteínas/química , Doenças dos Suínos/parasitologia , Animais , Equinococose/parasitologia , Echinococcus/genética , Echinococcus/imunologia , Echinococcus/isolamento & purificação , Eletroforese em Gel Bidimensional , Genótipo , Proteínas de Helminto/genética , Proteínas de Helminto/imunologia , Lipoproteínas/genética , Lipoproteínas/imunologia , Espectrometria de Massas , Proteômica , SuínosRESUMO
The laminated layer (LL) is the massive carbohydrate-rich structure that protects Echinococcus larvae, which cause cystic echinococcosis (hydatid disease) and alveolar echinococcosis. Increased understanding of the biochemistry of the LL is allowing a more informed analysis of its immunology. The LL not only protects the parasite against host attack but also shapes the overall immune response against it. Because of its dense glycosylation, it probably contains few T-cell epitopes, being important instead in T-cell independent antibody responses. Crucially, it is decoded in non-inflammatory fashion by innate immunity, surely contributing to the strong immune-regulation observed in Echinococcus infections. Defining the active LL molecular motifs and corresponding host innate receptors is a feasible and promising goal in the field of helminth-derived immune-regulatory molecules.
Assuntos
Equinococose/imunologia , Echinococcus/imunologia , Mucinas/imunologia , Imunidade Adaptativa , Animais , Anticorpos Anti-Helmínticos/imunologia , Antígenos de Helmintos/imunologia , Equinococose/parasitologia , Epitopos de Linfócito T/imunologia , Glicosilação , Interações Hospedeiro-Parasita , Humanos , Larva/química , Larva/imunologia , Mucinas/químicaRESUMO
Echinococcus vogeli infection in a hunter from the rain forest of French Guiana was confirmed by imaging and mitochondrial DNA sequence analysis. Serologic examination showed typical patterns for both alveolar and cystic echinococcosis. Polycystic echinococcis caused by E. vogeli may be an emerging parasitic disease in Central and South America.
Assuntos
Equinococose/diagnóstico , Idoso , Animais , Anticorpos Anti-Helmínticos/sangue , DNA Mitocondrial/química , Equinococose/cirurgia , Echinococcus/genética , Echinococcus/imunologia , Ensaio de Imunoadsorção Enzimática , Humanos , Masculino , Análise de Sequência de DNARESUMO
Echinococcosis is a worldwide zoonotic parasitic disease of humans and various herbivorous domestic animals (intermediate hosts) transmitted by the contact with wild and domestic carnivores (definitive hosts), mainly foxes and dogs. Recently, a vaccine was developed showing high levels of protection against one parasite haplotype (G1) of Echinococcus granulosus, and its potential efficacy against distinct parasite variants or species is still unclear. Interestingly, the EG95 vaccine antigen is a secreted glycosylphosphatydilinositol (GPI)-anchored protein containing a fibronectin type III domain, which is ubiquitous in modular proteins involved in cell adhesion. EG95 is highly expressed in oncospheres, the parasite life cycle stage which actively invades the intermediate hosts. After amplifying and sequencing the complete CDS of 57 Echinococcus isolates belonging to 7 distinct species, we uncovered a large amount of genetic variability, which may influence protein folding. Two positively selected sites are outside the vaccine epitopes, but are predicted to alter protein conformation. Moreover, phylogenetic analyses indicate that EG95 isoform evolution is convergent with regard to the number of beta-sheets and alpha-helices. We conclude that having a variety of EG95 isoforms is adaptive for Echinococcus parasites, in terms of their ability to invade different hosts, and we propose that a mixture of isoforms could possibly maximize vaccine efficacy.
Assuntos
Antígenos de Helmintos/genética , Antígenos de Helmintos/imunologia , Echinococcus/genética , Echinococcus/imunologia , Proteínas de Helminto/genética , Proteínas de Helminto/imunologia , Vacinas/genética , Vacinas/imunologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Primers do DNA/genética , DNA de Helmintos/genética , Equinococose/imunologia , Equinococose/parasitologia , Equinococose/prevenção & controle , Echinococcus/patogenicidade , Evolução Molecular , Interações Hospedeiro-Parasita/genética , Interações Hospedeiro-Parasita/imunologia , Humanos , Dados de Sequência Molecular , Filogenia , RNA de Helmintos/genética , RNA Mensageiro/genética , Seleção Genética , Homologia de Sequência de AminoácidosRESUMO
We evaluated prevalence of cystic echinococcosis (CE) in a central Peruvian Highland district by using 4 diagnostic methods: ultrasonography for 949 persons, radiography for 829, and 2 serologic tests for 929 (2 immunoblot formats using bovine hydatid cyst fluid [IBCF] and recombinant EpC1 glutathione S-transferase [rEpC1-GST] antigens). For the IBCF and rEpC1-GST testing, prevalence of liver and pulmonary CE was 4.7% and 1.1% and seropositivity was 8.9% and 19.7%, respectively. Frequency of seropositive results for IBCF and rEpC1-GST testing was 35.7% and 16.7% (all hepatic cysts), 47.1% and 29.4% (hepatic calcifications excluded), and 22.2% and 33.3% (lung cysts), respectively. Weak immune response against lung cysts, calcified cysts, small cysts, and cysts in sites other than lung and liver might explain the poor performance of the serodiagnostic tests. We confirm that CE is highly endemic to Peru and emphasize the limited performance of available serologic assays in the field.
Assuntos
Anticorpos Anti-Helmínticos/sangue , Equinococose Hepática , Equinococose Pulmonar , População Rural , Adulto , Animais , Antígenos de Helmintos/imunologia , Pré-Escolar , Equinococose Hepática/diagnóstico , Equinococose Hepática/diagnóstico por imagem , Equinococose Hepática/epidemiologia , Equinococose Pulmonar/diagnóstico , Equinococose Pulmonar/diagnóstico por imagem , Equinococose Pulmonar/epidemiologia , Echinococcus/imunologia , Doenças Endêmicas , Feminino , Humanos , Immunoblotting , Fígado/diagnóstico por imagem , Pulmão/diagnóstico por imagem , Masculino , Peru/epidemiologia , Prevalência , Radiografia , UltrassonografiaRESUMO
Immunodiagnosis in sheep presents problems of sensitivity and specificity, limiting its applicability in surveillance systems. The objective of this study was to develop a sensitive, specific and accessible technique for diagnosing cystic echinococcosis in naturally infected sheep and to evaluate the validity of necropsy as a reference test. A total of 247 sheep were studied at slaughterhouses, confirming the parasitological diagnosis with histology. Serum was processed with enzyme immunoassay (EIA) using three antigen preparations: total hydatid liquid (LHT), purified fraction of LHT (S2B) and purified lipoprotein (B). Western Blot (WB) was used as a control. EIA proved effective for differentiating Echinococcus granulosus from larval stage of Taenia hydatigena and intestinal cestodes in all three antigen preparations. Serums from macroscopically negative sheep were reactive to EIA and positive with WB. In the whole flock, sensitivity was 89.2% for LHT, 80.0% for S2B and 86.4% for B. Sensitivity in lambs was 78.6% for LHT, 75.0% for S2B and 64.3% for B. Macroscopic diagnosis at the time of slaughter was found to have limitations as a reference test for immunodiagnosis of cystic equinococcosis in sheep, so it was necessary to include histology and WB as reference tests. LHT was the antigen preparation of greatest value and EIA proved to be a sensitive and specific technique, adequate for surveillance systems and for evaluating control programmes.
Assuntos
Antígenos de Helmintos , Equinococose/veterinária , Echinococcus/imunologia , Técnicas Imunoenzimáticas/veterinária , Doenças dos Ovinos/diagnóstico , Matadouros , Animais , Antígenos de Helmintos/imunologia , Western Blotting/veterinária , Diagnóstico Diferencial , Equinococose/diagnóstico , Feminino , Técnicas Imunoenzimáticas/métodos , Técnicas Imunoenzimáticas/normas , Masculino , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Vigilância de Evento Sentinela/veterinária , Ovinos , Taenia/imunologiaRESUMO
Twenty-seven PCR-derived antigen B (AgB) nucleotide sequences from four Echinococcus species (Echinococcus granulosus, Echinococcus multilocularis, Echinococcus oligarthrus and Echinococcus vogeli) were aligned with 78 already published sequences, to generate a maximum likelihood phylogeny of the AgB multigene family. The phylogenetic analysis confirms that the family is constituted by four groups of genes present in each one of the four species (AgB1, AgB2, AgB3 and AgB4), and suggests that it originated by ancient duplication events preceding speciation within the genus. AgB5 sequences, which had been formerly suggested to correspond to a putatively new AgB subunit, cluster with AgB3. Likelihood tests suggest that AgB gene evolution may have been driven by heterogeneous selection pressures acting on particular AgB1, AgB3 and AgB4 codons. No selection is detected in AgB2. We discuss implications of our findings in terms of AgB biology and its use as a diagnostic tool.
Assuntos
Adaptação Fisiológica/genética , Antígenos de Helmintos/genética , Echinococcus/genética , Evolução Molecular , Genes de Helmintos , Proteínas de Helminto/genética , Lipoproteínas/genética , Sequência de Aminoácidos , Animais , Echinococcus/classificação , Echinococcus/imunologia , Dados de Sequência Molecular , Família Multigênica , Seleção Genética , Especificidade da EspécieRESUMO
Cystic echinococcosis (CE) caused by the larval form of Echinococcus granulosus is a major public health problem in sheep-raising regions of the World. This study compared portable ultrasound with the enzyme-linked immunoelectrotransfer blot (EITB) assay as screening methods to estimate the prevalence of human CE in a remote village in the Peruvian Andes. Three hundred eighty-nine villagers were examined by portable ultrasound and blood samples were drawn by venipuncture. Sera were collected and tested for antibodies against CE using an EITB assay. Cystic lesions were classified based on their ultrasound morphologic characteristics. The prevalence of human CE using portable ultrasound and the EITB assay were 4.9% and 2.6%, respectively. Fifty-three percent of subjects with CE were EITB positive. Portable ultrasound was well received by the community, augmented CE detection and allowed a faster estimate of human infection than the EITB assay.
Assuntos
Equinococose/diagnóstico , Equinococose/epidemiologia , Echinococcus/isolamento & purificação , Programas de Rastreamento/métodos , Sistemas Automatizados de Assistência Junto ao Leito , Ultrassonografia/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Anticorpos Anti-Helmínticos/sangue , Criança , Equinococose/imunologia , Echinococcus/imunologia , Doenças Endêmicas/prevenção & controle , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Peru/epidemiologia , Prevalência , Reprodutibilidade dos Testes , Estudos Soroepidemiológicos , Ultrassonografia/instrumentaçãoRESUMO
This investigation aimed to design a strategy for echinococcosis control in Santana do Livramento county, an endemic area in state of Rio Grande do Sul (Brazil). Fecal samples from 65 dogs were obtained from urban, suburban and rural areas. Purging with Arecoline Bromhidrate (AB) was done to visualize Echinococcus granulosus, and Enzyme Linked Immunosorbent Assay (ELISA) was performed to detect parasite coproantigen. Samples were obtained at the beginning and at the end of treatment with Praziquantel. A third fecal sampling was also done in rural areas four months after the end of treatment. Each dog was treated immediately after the first purging and every 30 days for eight months. In urban and suburban areas no infected dogs were found. In rural areas, first evaluation showed 11.36% and 27.69% of infected dogs by AB and ELISA, respectively. No infected dogs were diagnosed in the second evaluation and in the third evaluation 36.84% and 47.37% infected dogs were identified by AB and ELISA, respectively. Medication program to combat dog infection resulted in successful interruption of parasite transmission, but the project failed to create awareness of the need for dog prophylaxis among rural populations as well as to establish a permanent control program in this municipality.
Assuntos
Anti-Helmínticos/uso terapêutico , Doenças do Cão/prevenção & controle , Equinococose/veterinária , Echinococcus/isolamento & purificação , Praziquantel/uso terapêutico , Animais , Brasil/epidemiologia , Doenças do Cão/epidemiologia , Cães , Equinococose/epidemiologia , Equinococose/prevenção & controle , Echinococcus/imunologia , Ensaio de Imunoadsorção Enzimática , Fezes/parasitologia , Contagem de Ovos de Parasitas , População Rural , População UrbanaRESUMO
Recent studies have demonstrated that the Echinococcus granulosus antigen B (AgB) interferes with the intermediate hosts' immune response and is encoded by a multigene family. The number of members within the family is still uncertain, but there are several evidences of a large genetic variability. The E. granulosus AgB genomic sequences available in nucleotide databases can be grouped into four clades, corresponding to genes EgAgB1, EgAgB2, EgAgB3 and EgAgB4. In the present study, we use PCR amplifications followed by cloning and sequencing to evaluate the genetic variability for AgB isoforms. Two pairs of primers were independently used for PCR amplification. Both PCR reactions from each of three isolated protoscolex (larvae) were cloned in a plasmid vector and the plasmid inserts of 30 colonies from each cloning experiment were sequenced. Using phylogenetic tools, the 113 EgAgB clones are classified as follows: 25 are related to EgAgB1, 24 to EgAgB2, 9 to EgAgB3 and 39 to EgAgB4. The remaining 16 clones form a separate cluster, which we name EgAgB5, more closely related to EgAgB3 than to any of the other genes. Within each gene group, a number of variant sequences occur, which differ from one another by one or few nucleotides. One EgAgB3 clone has a premature stop codon (pseudogene) and an EgAgB2 clone lacks the region corresponding to the intron. The overall variation cannot be explained by differences among the asexual protoscoleces, or by experimental artifacts. Using Echinococcuss AgB genes from other species/strains as outgroups, neutrality is rejected for EgAgB2, and balancing selection is detected for EgAgB5, which also seems to be involved in gene conversion. We suggest that EgAgB1-EgAgB5 represent a family of contingency genes, that is, genes that are variably expressed, so that some but not others are expressed in each individual parasite. Contingency genes are common in parasitic protozoa and other microparasites, but the EgAgB family is the first set identified in a multicellular parasite.
Assuntos
Echinococcus/genética , Evolução Molecular , Conversão Gênica , Proteínas de Helminto/genética , Lipoproteínas/genética , Seleção Genética , Alelos , Animais , Antígenos de Helmintos/genética , Sequência de Bases , Clonagem Molecular , DNA de Helmintos/química , DNA de Helmintos/genética , Echinococcus/imunologia , Dados de Sequência Molecular , Filogenia , Polimorfismo Genético , Alinhamento de Sequência , Análise de Sequência de DNA , Homologia de Sequência do Ácido NucleicoRESUMO
Local and systemic immune responses were studied in six dogs experimentally infected with the dog/sheep tapeworm Echinococcus granulosus. All dogs developed similar IgG antibody response to parasite antigens. In contrast, IgE and IgA responses differed widely. No relationship between IgA responses and parasite burden at the end of the infection were observed. Further, clear differences in the anti-parasite IgA response in serum as compared with specific IgA forming cells in mesenteric lymph nodes were observed within the same dog. An inverse association of anti-parasite IgE and parasite load seemed to be present, with the strongest IgE response in the one dog that had no worms in the intestine at the end of the experiment. No differences were observed in the numbers of intestinal mast cells and goblet cells among all infected dogs. However, the dog with no detectable parasite load had a marked reduction of detected mast cells in the submuscular and muscular layer of the mucosa. Our data give new insight into the immune response of dogs during E. granulosus infection and provide information that may be useful for the rational design of vaccines for the control of hydatid disease.
Assuntos
Doenças do Cão/imunologia , Doenças do Cão/parasitologia , Equinococose/imunologia , Equinococose/veterinária , Echinococcus/imunologia , Animais , Anticorpos Anti-Helmínticos/sangue , Western Blotting/veterinária , Contagem de Células/veterinária , Cães , Equinococose/parasitologia , Ensaio de Imunoadsorção Enzimática/veterinária , Células Caliciformes/imunologia , Células Caliciformes/parasitologia , Histocitoquímica/veterinária , Isotipos de Imunoglobulinas/sangue , Intestino Delgado/imunologia , Intestino Delgado/parasitologia , Linfonodos/imunologia , Linfonodos/parasitologia , Mastócitos/imunologia , Mastócitos/parasitologia , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/parasitologiaRESUMO
Helminth antigens were investigated in the search for accessible heterologous antigens capable to discriminate different helminthiases, by the enzyme linked immunosorbent assay (ELISA) and the immunoblot assay (IB). Antigens used were: Taenia solium cysticercus total saline (Tso); Taenia crassiceps cysticercus vesicular fluid (Tcra-VF); T. crassiceps cysticercus glycoproteins (Tcra-GP and Tcra-(18-14)-GP); Toxocara canis larva excretory-secretory (TES); Schistosoma mansoni adult total saline (Sm) and Echinococcus granulosus hydatid fluid (Eg). The assayed sera were from patients with: cysticercosis (n = 18); toxocariasis (n = 40); schistosomiasis (n = 19) and hydatidosis (n = 50) with proven clinical and laboratory diagnosis, and sera from rabbits immunized with Tso, Tcra-VF, TES and Eg. Cross-reactivity occurred mostly between infections caused by Taenia and Echinococcus or in immunized rabbits, by ELISA. Moreover, the cross-reactivity among helminthiases was found with the use of antigens belonging to phylogenetically related parasite species, Eg, Tso and Tcra-VF, by sharing same antigenic components. Lower cross-reactivities were obtained by IB technique, when only peptides were considered as antigens, and the use of T. crassiceps purified glycoproteins demonstrated high sensitivity and specificity in the diagnosis of human cysticercosis, similarly to that using homologous antigen (Tso) by the same technique.
Assuntos
Antígenos de Helmintos/sangue , Echinococcus/imunologia , Helmintíase/imunologia , Schistosoma mansoni/imunologia , Taenia solium/imunologia , Animais , Antígenos de Helmintos/imunologia , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Humanos , CoelhosRESUMO
One hundred and six dogs (61 males and 45 females) were examined for Echinococcus granulosus infection in a farming cooperative in the central highlands of Peru during November 1998. Canine echinococcosis was diagnosed using direct microscopic examinations of purged feces following arecoline purging and a coproantigen-detection enzyme-linked immunosorbent assay (ELISA) for E. granulosus. Mean age was 2 years with a range of 3 months to 9 years. The overall prevalence of canine echinococcosis using the ELISA test was 79% (84/106). Seventy-four dogs were successfully purged with arecoline. The frequency of canine echinococcosis was 82 (61/74) and 34% (25/74) by the coproantigen ELISA test and arecoline purging, respectively. The sensitivity and specificity of the coproantigen ELISA test was 88 and 95%, respectively. We found this assay to be especially advantageous in remote geographical areas. In future control programs against echinococcosis in Peru and other areas where E. granulosus is endemic the coproantigen ELISA should be used for the surveillance of the dog population.
Assuntos
Antígenos de Helmintos/análise , Doenças do Cão/diagnóstico , Equinococose/veterinária , Echinococcus/isolamento & purificação , Ensaio de Imunoadsorção Enzimática/veterinária , Animais , Arecolina/uso terapêutico , Agonistas Colinérgicos/uso terapêutico , Doenças do Cão/tratamento farmacológico , Doenças do Cão/epidemiologia , Cães , Equinococose/diagnóstico , Equinococose/tratamento farmacológico , Equinococose/epidemiologia , Echinococcus/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Fezes/parasitologia , Feminino , Masculino , Peru/epidemiologia , Prevalência , Sensibilidade e EspecificidadeRESUMO
This article focuses on the initiation pathway of mucin-type O-glycosylation in helminth parasites. The presence of the GalNAc-O-Ser/Thr structure, also known as Tn antigen, a truncated determinant related to aberrant glycosylation in mammal cells, and the activity of the UDP-GalNAc:polypeptide N-acetyl-galactosaminyltransferase (ppGaNTase), the enzyme responsible for its synthesis, were studied in species from major taxonomic groups. Tn reactivity was determined in extracts from Taenia hydatigena, Mesocestoides corti, Fasciola hepatica, Nippostrongylus brasiliensis, and Toxocara canis using the monoclonal antibody 83D4. The Tn determinant was revealed in all preparations, and multiple patterns of Tn-bearing glycoproteins were observed by immunoblotting. Additionally, the first evidence that helminth parasites express ppGaNTase activity was obtained. This enzyme was studied in extracts from Echinococcus granulosus, F. hepatica, and T. canis by measuring the incorporation of UDP-(3H)GalNAc to both deglycosylated ovine syalomucin (dOSM) and synthetic peptide sequences derived from tandem repeats of human mucins. Whereas significant levels of ppGaNTase activity were detected in all the extracts when dOSM was used as a multisite acceptor, it was only observed in F. hepatica and E. granulosus extracts when mucin-derived peptides were used, suggesting that T. canis ppGaNTase enzyme(s) may represent a member of the gene family with a more restricted specificity for worm O-glycosylation motifs. The widespread expression of Tn antigen, capable of evoking both humoral and cellular immunity, strongly suggests that simple mucin-type O-glycosylation does not constitute an aberrant phenomenon in helminth parasites.
Assuntos
Antígenos Glicosídicos Associados a Tumores/metabolismo , Helmintos/metabolismo , N-Acetilgalactosaminiltransferases/metabolismo , Animais , Antígenos Glicosídicos Associados a Tumores/química , Western Blotting , Bovinos , Cães , Echinococcus/enzimologia , Echinococcus/imunologia , Echinococcus/metabolismo , Eletroforese em Gel de Poliacrilamida , Fasciola hepatica/enzimologia , Fasciola hepatica/imunologia , Fasciola hepatica/metabolismo , Glicopeptídeos/metabolismo , Glicoproteínas/análise , Glicosilação , Helmintos/enzimologia , Helmintos/imunologia , Humanos , Mesocestoides/enzimologia , Mesocestoides/imunologia , Mesocestoides/metabolismo , Camundongos , Nippostrongylus/enzimologia , Nippostrongylus/imunologia , Nippostrongylus/metabolismo , Ratos , Ratos Wistar , Taenia/enzimologia , Taenia/imunologia , Taenia/metabolismo , Toxocara canis/enzimologia , Toxocara canis/imunologia , Toxocara canis/metabolismo , Polipeptídeo N-AcetilgalactosaminiltransferaseRESUMO
Several recombinant clones expressing antigens from Echinococcus granulosus were isolated previously from a parasite cDNA library using cystic hydatid disease (CHD) patients' sera or rabbit hyperimmune antiserum against a lipoproteic fraction from bovine cyst fluid. Six of these antigens were expressed in Escherichia coli and the purified recombinant proteins were tested in enzyme-linked immunosorbent assay (ELISA) for specific IgG with a panel of sera from patients with surgically confirmed (n = 58) or immunologically diagnosed (n = 71) CHD. Sera from clinically normal individuals (n = 203) and sera from individuals with other helminthic infections (n = 65) were assayed for the assessment of specificity. A cut-off value was determined by receiver-operating-characteristic plots for each antigen. A recombinant antigen B subunit (AgB8/2) presented the highest sensitivity (93.1%), considering the group of sera from patients with CHD surgically confirmed, and specificity (99.5%) and is proposed as the basis for an immunodiagnostic test. The other recombinant antigens tested presented sensitivities between 58.6% and 89.7%, and three of them were considered of complementary value. In subclass-specific ELISA, different IgG isotypes showed dominance in the response for each of the recombinant antigens. There was a clear predominance of IgG4 response for all antigens tested, indicating that this would be the subclass of choice to be assessed for these recombinant proteins.