Characterization and evaluation of three new recombinant antigens of Taenia solium for the immunodiagnosis of cysticercosis.

Cysticerci of Taenia solium cause cysticercosis, with neurocysticercosis (NCC) as the major pathology. Sensible and specific recombinant antigens would be an source of antigen for immunodiagnosis. The objective of this work was the molecular characterization and evaluation, of three news recombinant antigens (TsF78, TsP43 and TsC28), obtained by screening of a Taenia solium cDNA library. The three cDNA were analysed by bioinformatic programs, subcloned and expresed. The purified proteins were evaluated in ELISA using cyst fluid as control. TsF78 is filamina, TsP43 a peroxidase and TsC28 collagen XV. The sensitivity and specificity of the recombinant proteins were; TsF78 93.8 % and 95.0 %, TsP62 91.7 % and 93.3 %, TsC28 85.4 % and 93.3 %, respectively, while the cyst fluid showed a sensitivity of 87.5 % and a specificity of 76.7 %. Given its high sensitivity and specificity, the recombinant proteins TsF78 and TsP62 could be used in the diagnosis of cysticercosis.

Evagination of metacestodes of the WFU strain of Taenia crassiceps and evaluation of the impact of immune suppression of hamsters during tapeworm development.

Taeniosis-cysticercosis caused by Taenia crassiceps (Zeder, 1800) is a useful experimental model for biomedical research, in substitution of Taenia solium Linnaeus, 1758, studied during decades to develop effective vaccination, novel anti-helminthic drugs and diagnostic tools. Cysticercosis in mouse (Mus musculus Linnaeus) is achieved by the larval subculturing of the Wake Forest University (WFU) strain of T. crassiceps. Golden hamster, Mesocricetus auratus (Waterhouse), has been shown to be the most suitable host for adult forms of parasite in experimental taeniosis. Metacestodes of T. crassiceps WFU multiply by budding without restrictions once inoculated into the mouse, while the number of tapeworms developed from these larvae in hamsters remains highly variable. Three objectives have been proposed to improve the infection of T. crassiceps WFU in hamsters: (1) to re-evaluate the need of immune suppression; (2) to investigate the advantage of infecting hamsters with metacestodes with in vitro protruded scolices; and (3) to compare a number of tapeworms developed from metacestodes subcultured in hamsters against those proliferated in mice. Our results demonstrated that when the evagination of murine metacestodes was high, the number of T. crassiceps WFU adults obtained from hamsters was also high. Immunosuppressive treatment remains relevant for this experimental rodent model. The hamster-to-hamster cysticercosis-taeniosis by T. crassiceps overcame the mouse-to-hamster model in the yield of adult specimens. In vitro scolex evagination and metacestode asexual proliferation in hamsters place this rodent model by T. crassiceps WFU as the most affordable experimental models with taeniids.

Seroepidemiological evidence for Taenia solium taeniasis/cysticercosis in three Venezuelan rural communities.

Taenia solium is the most common parasite infection of the brain, causing neurocysticercosis and typically found in rural communities with free-ranging pigs. Identification of transmission in rural areas is essential for its control. Risk factors and transmission of the parasite were evaluated in three rural Venezuelan communities (Valle del Rio and Potrero Largo, Cojedes state; and Palmarito, Portuguesa state) by a questionnaire (112 households) and coprological (492 samples) and serological (433 human and 230 porcine sera) analysis, respectively. Typical risk factors were found in all three communities: free-foraging pig husbandry, deficient sanitary conditions, high open defecation and ignorance of the parasite life cycle. Coprological examinations revealed a high level of soil-transmitted parasites. Importantly, two T. solium adult worm carriers were identified in each of the three communities. Anti-metacestode antibodies and the HP10 secreted metacestode glycoprotein were detected at significant levels in human and porcine sera in Valle del Rio, Potrero Largo and Palmarito. In conclusion, these communities may be considered to be endemic for taeniasis/cysticercosis, and the instigation of an appropriate control programme is recommended.

Clustering of Necropsy-Confirmed Porcine Cysticercosis Surrounding Taenia solium Tapeworm Carriers in Peru.

The pork tapeworm, Taenia solium, is among the leading causes of preventable epilepsy in the world and is common in rural areas of developing countries where sanitation is limited and pigs have access to human feces. Prior studies in rural villages of Peru have observed clusters of T. solium cysticercosis among pigs that live near human tapeworm carriers. Such spatial analyses, however, have been limited by incomplete participation and substandard diagnostic tests. In this study, we evaluated the association between necropsy-confirmed cysticercosis in pigs and their distance to T. solium tapeworm carriers in six villages in northern Peru. A total of six (1.4%) tapeworm carriers were detected using copro-antigen enzyme-linked immunosorbent assay and seven of 10 (70%) pigs belonging to the tapeworm carriers were found with viable cyst infection on necropsy. This was significantly greater than the prevalence of viable cyst infection among pigs living < 500 m (11%) and > 500 m (0.5%) from a tapeworm carrier (P < 0.001 for distance trend). Similar statistically significant prevalence gradients were observed after adjustment for possible confounders and for other pig-level outcomes including infection with > 10 viable cysts, degenerated cyst infection, and serological outcomes. This investigation confirms that porcine cysticercosis clusters strongly around tapeworm carriers in endemic rural regions of northern Peru and supports interventions that target these hotspots.

Taenia crassiceps antigens induce a Th2 immune response and attenuate injuries experimentally induced by neurotoxoplasmosis in BALB/c mice.

Toxoplasma gondii is a pathogenic agent responsible for causing both systemic and local disease which elicits a typically pro-inflammatory, Th1 immune response. Taenia crassiceps antigen induces a Th2 immune response that immunomodulates Th1 based infections. Therefore the aim of this study was to evaluate whether T. crassiceps cysticerci antigens are able to modulate the inflammatory response triggered in experimental neurotoxoplasmosis (NT). BALB/c mice were inoculated with T. gondii cysts and/or cysticerci antigens and euthanized at 60 and 90days after inoculation (DAI). The histopathology of the brains and cytokines produced by spleen cells culture were performed. The animals from the NT group, 90DAI (NT90), presented greater intensity of lesions such as vasculitis, meningitis and microgliosis and cytokines from Th1 profile characterized by high levels of IFN-gamma. While in the T. crassiceps antigens group, 60DAI, there were more discrete lesions and high levels of IL-4, a Th2 cytokine. In the NT co-inoculated with cysticerci antigens group the parenchyma lesions were more discrete with lower levels of IFN-gamma and higher levels of IL-4 when compared to NT90. Therefore the inoculation of T. crassiceps antigens attenuated the brain lesions caused by T. gondii inducing a Th2 immune response.

[Seroprevalence and risk factors of cysticercosis in two rural communities in Anzoátegui state, Venezuela].

INTRODUCTION: Cysticercosis is caused by Taenia solium cysticerci, which are located mainly in the central nervous system causing neurocysticercosis. In Venezuela, few epidemiological studies on this disease have been conducted. OBJECTIVE: To determine the seroprevalence and risk factors for cysticercosis in two rural communities in Anzoátegui state. MATERIAL AND METHODS: We conducted a survey to collect data on possible risk factors and signs and symptoms of the disease, and we took 182 samples in two communities, Boquerón and Punto Lindo. Detection of IgG antibodies against T. solium cysticerci was performed by ELISA. RESULTS: Seroprevalence in Boquerón was 3.3%; due to the low number of seropositives the statistical analysis was not possible. However, the three seropositive persons had knowledge of the disease, and a history of consumption of undercooked pork meat, and presence of headache. In Punto Lindo, seroprevalence was 28.9%. There were no significant differences by sex or age; however, we found more seropositives among individuals younger than 20 years. With regard to risk factors and signs and symptoms, significant associations were found with consumption of undercooked pork (OR=18; 95% CI: 5.78 to 55.9), headaches (OR=3.6; 95% CI: 1.15 to 11.4), seizures (OR=18.9; 95% CI: 2.15 to 166.5) and visual problems (OR=5.7; 95% CI: 2.13 to 15.34). CONCLUSIONS: The results showed low transmission of cysticercosis in Boquerón, and high in Punto Lindo, where the high prevalence in children suggests recent transmission.

Seroprevalencia y factores de riesgo de cisticercosis en dos comunidades rurales del norte del estado Anzoátegui, Venezuela / Seroprevalence and risk factors of cysticercosis in two rural communities in Anzoátegui state, Venezuela

Resumen Introducción. La cisticercosis es causada por las larvas de Taenia solium, las cuales se localizan principalmente en el sistema nervioso central y causan neurocisticercosis. En Venezuela se han hecho pocos estudios epidemiológicos de esta enfermedad. Objetivo. Determinar la seroprevalencia y los factores de riesgo de la cisticercosis en dos comunidades rurales del estado Anzoátegui, Venezuela. Materiales y métodos. Se hizo una encuesta para recolectar datos sobre los posibles factores de riesgo y los signos y síntomas de la enfermedad, y se tomaron 182 muestras de los habitantes de las comunidades de Boquerón y Punto Lindo. Se determinaron los anticuerpos IgG contra cisticercos de T. solium mediante ensayo inmunoenzimático (ELISA). Resultados. En Boquerón, se presentó una seroprevalencia de 3,3 %; debido al bajo número de muestras positivas no se pudo hacer el análisis estadístico. Sin embargo, las tres personas positivas tenían conocimiento de la enfermedad, antecedentes de tenencia de cerdos no confinados, consumo de carne de cerdo semicruda y cefalea frecuente. En Punto Lindo, la seroprevalencia fue de 28,9 %. No hubo diferencias estadísticamente significativas en cuanto al sexo y la edad, sin embargo, se encontró mayor frecuencia en menores de 20 años. Con respecto a los factores de riesgo y los signos y síntomas, se encontró asociación significativa con el consumo de carne de cerdo semicruda (odds ratio, OR=18; IC95% 5,78-55,9), cefalea frecuente (OR=3,6; IC95% 1,15-11,4), convulsiones (OR=18,9; IC95% 2,15-166,5) y problemas de visión (OR=5,7; IC95% 2,13-15,34). Conclusión. Los resultados demostraron que había poca transmisión de cisticercosis en Boquerón, pero mucha en Punto Lindo, sobre todo en niños, lo cual sugeriría que se trata de transmisión reciente.

Abstract Introduction: Cysticercosis is caused by Taenia solium cysticerci, which are located mainly in the central nervous system causing neurocysticercosis. In Venezuela, few epidemiological studies on this disease have been conducted. Objective: To determine the seroprevalence and risk factors for cysticercosis in two rural communities in Anzoátegui state. Material and methods: We conducted a survey to collect data on possible risk factors and signs and symptoms of the disease, and we took 182 samples in two communities, Boquerón and Punto Lindo. Detection of IgG antibodies against T. solium cysticerci was performed by ELISA. Results: Seroprevalence in Boquerón was 3.3%; due to the low number of seropositives the statistical analysis was not possible. However, the three seropositive persons had knowledge of the disease, and a history of consumption of undercooked pork meat, and presence of headache. In Punto Lindo, seroprevalence was 28.9%. There were no significant differences by sex or age; however, we found more seropositives among individuals younger than 20 years. With regard to risk factors and signs and symptoms, significant associations were found with consumption of undercooked pork (OR=18; 95% CI: 5.78 to 55.9), headaches (OR=3.6; 95% CI: 1.15 to 11.4), seizures (OR=18.9; 95% CI: 2.15 to 166.5) and visual problems (OR=5.7; 95% CI: 2.13 to 15.34). Conclusions: The results showed low transmission of cysticercosis in Boquerón, and high in Punto Lindo, where the high prevalence in children suggests recent transmission.

IFN-gamma role in granuloma formation in experimental subcutaneous cysticercosis.

Cysticercosis is an infection caused by the metacestode larval stage of Taenia parasites in tissues and elicits a host-parasite reaction in which the immune response may be decisive in the disease development. The aim of this study was to evaluate the role of IFNγ (IFN-gamma) in the experimental model of subcutaneous infection with Taenia crassiceps (T. crassiceps) cysticerci using IFNγ knockout mice. Male C57BL/6 and C57BL/6 KO IFNγ mice 8-12 weeks of age were inoculated with T. crassiceps cysticerci into the subcutaneous tissue of the dorsum. At 7 and 30 (acute phase), 60 and 90 (chronic phase) days post infection, animals from each group had their blood and the subcutaneous tissues collected for serologic and pathological studies. IFNγ and IL-4 were dosed and the histopathological analysis was performed. In the presence of IFNγ there was the establishment of a mixed Th1/Th2 systemic immune profile. This profile also locally induced the granuloma formation which was constituted by cells that played important roles in the parasitary destruction and that were likely associated to the Th1 axis of mixed immune response. On the other hand, the absence of IFNγ appears to favor the parasitary growth which may be related to the development of a systemic Th2 immune response. This profile influenced the granuloma formation with immunoregulatory properties and appears to be important in the collagen synthesis.

Expression of Multiple Taenia Solium Immunogens in Plant Cells Through a Ribosomal Skip Mechanism.

Taenia solium cysticercosis is a major parasitic disease that affects the human health and the economy in underdeveloped countries. Porcine cysticercosis, an obligatory stage in the parasite life cycle, is a suitable target for vaccination. While several recombinant and synthetic antigens proved to be effective as vaccines, the cost and logistic difficulties have prevented their massive use. Taking this into account, a novel strategy for developing a multi-epitope low-cost vaccine is herein explored. The S3Pvac vaccine components (KETc1, KETc12, KETc7, and GK1 [KETc7]) and the protective HP6/TSOL18 antigen were expressed in a Helios2A polyprotein system, based on the 'ribosomal skip' mechanism mediated by the 2A sequence (LLNFDLLKLAGDVESNPG-P) derived from the Foot-and-mouth disease virus, which induces self-cleavage events at a translational level. This protein arrangement was expressed in transgenic tobacco cells. The inserted sequence and its transcript were detected in several Helios2A lines, with some lines showing recombinant protein accumulation levels up to 1.3 µg/g of fresh weight in leaf tissues. The plant-derived Helios2A vaccine was recognized by antibodies in the cerebral spinal fluid from neurocysticercosis patients and elicited specific antibodies in BALB/c immunized mice. These evidences point to the Helios2A polyprotein as a promising system for expressing multiple antigens of interest for vaccination and diagnosis in one single construction.

Diethylstilbestrol exposure in neonatal mice induces changes in the adulthood in the immune response to taenia crassiceps without modifications of parasite loads.

Industrial growth has increased the exposition to endocrine disruptor compounds (EDC's), which are exogenous agents with agonist or antagonist action of endogenous steroid hormones that may affect the course of parasite infections. We wanted to determine if the exposure to diethylstilbestrol (DES), an estrogen agonist, to both male and female mice affected the immune response and their susceptibility to T. crassiceps cysticercosis. In all infected groups, females showed higher parasite loads than males, and neonatal DES administration did not modify this pattern. In the spleen, noninfected mice showed sex-related differences in the percentage of the CD8+ subpopulation, but DES decreased the percentage of CD3+, CD19+, and CD8+ subpopulations in infected mice. In the mesenteric lymphatic node (MNL), DES showed a dimorphic effect in the percentage of CD19+ cells. Regarding estrogen receptor alpha (ER-α) expression, DES treatment induced a reduction in the expression of this receptor in both noninfected female and male mice in the spleen, which was decreased only in males in CD3+ and CD8+ lymphocytes in MNL cell subpopulations. Our study is the first one to demonstrate that DES neonatal treatment in male and female mice affects the immune cell percentage, without effect on the susceptibility to T. crassiceps cysticercosis.

[Assessment of dot blot tests and latex agglutination for cysticercosis diagnostic in Peru]. / Evaluación de las pruebas dot blot y aglutinación de látex para el diagnóstico de cisticercosis en Perú

In order to evaluate dot blot tests and latex agglutination for the detection of human cysticercosis with liquid antigen of Taenia solium cysticerci, 125 human sera were used, of which 60 were from people with cysticercosis confirmed by Western Blot, 45 with other parasitic diseases and 20 apparently healthy. The optimal concentration of antigen to impregnate dot blot strips was 0.01 ug/uL, and to impregnate the latex particles was 0.092 ug/uL. For the dot blot test, a sensitivity of 100% and specificity of 87.7% was found. For latex agglutination, a sensitivity of 93.3% and specificity of 89.2% was found. Both tests may be useful and feasible to implement alternatives of serological diagnosis in laboratories in endemic areas of Peru.

Immunology of Taenia solium taeniasis and human cysticercosis.

The life cycle of Taenia solium, the pork tapeworm, is continuously closed in many rural settings in developing countries when free roaming pigs ingest human stools containing T. solium eggs and develop cysticercosis, and humans ingest pork infected with cystic larvae and develop intestinal taeniasis, or may also accidentally acquire cysticercosis by faecal-oral contamination. Cysticercosis of the human nervous system, neurocysticercosis, is a major cause of seizures and other neurological morbidity in most of the world. The dynamics of exposure, infection and disease as well as the location of parasites result in a complex interaction which involves immune evasion mechanisms and involutive or progressive disease along time. Moreover, existing data are limited by the relative lack of animal models. This manuscript revises the available information on the immunology of human taeniasis and cysticercosis.

Evaluación de las pruebas dot blot y aglutinación de látex para el diagnóstico de cisticercosis en Perú / Assessment of dot blot tests and latex agglutination for cysticercosis diagnostic in Peru

Con el objetivo de evaluar las pruebas dot blot y aglutinación de látex para la detección de cisticercosis humana con antígeno de líquido de cisticerco de Taenia solium, se usaron 125 sueros humanos, de los cuales 60 procedían de personas con cisticercosis confirmada por Western Blot, 45 de personas con otras enfermedades parasitarias y 20 de personas aparentemente sanas. La concentración óptima del antígeno para impregnar las tiras dot blot fue de 0,01 ug/uL, y para impregnar las partículas de látex fue de 0,092 ug/uL. Para la prueba dot blot se encontró una sensibilidad del 100% y especificidad del 87,7%; para la aglutinación de látex una sensibilidad del 93,3% y especificidad del 89,2%. Ambas pruebas podrían ser de utilidad y factibles de implementar como alternativas de diagnóstico serológico en laboratorios de áreas endémicas del Perú.

In order to evaluate dot blot tests and latex agglutination for the detection of human cysticercosis with liquid antigen of Taenia solium cysticerci, 125 human sera were used, of which 60 were from people with cysticercosis confirmed by Western Blot, 45 with other parasitic diseases and 20 apparently healthy. The optimal concentration of antigen to impregnate dot blot strips was 0.01 ug/uL, and to impregnate the latex particles was 0.092 ug/uL. For the dot blot test, a sensitivity of 100% and specificity of 87.7% was found. For latex agglutination, a sensitivity of 93.3% and specificity of 89.2% was found. Both tests may be useful and feasible to implement alternatives of serological diagnosis in laboratories in endemic areas of Peru.

Immunological variation in Taenia solium porcine cysticercosis: measurement on the variation of the antibody immune response of naturally infected pigs against antigens extracted from their own cysticerci and from those of different pigs.

Although it is widely assumed that both antigen and host immunological variability are involved in the variable intensity of natural porcine infections by Taenia solium (T. solium) cysticercis and success of immunodiagnostic tests vaccines, the magnitude of such combined variability has not been studied or measured at all. In this paper we report statistical data on the variability of the antibody response of naturally infected pigs against the antigens extracted from the vesicular fluids of their own infecting cysts (variance within pigs) and against antigen samples extracted from cysts of other cysticercotic pigs (variance among pigs). The variation between pigs was greater than the inter-pigs variations, which suggests that a concomitant immunity process prevents the establishment of cysts coming from a subsequent challenge. In so doing, we found that there is not a single antigenic band that was recognized by all hosts and that antigens varied among the cysts within the same pigs as well as among pigs. Our results may be valuable for the improvement of immunodiagnostic tests and of effective vaccines against naturally acquired porcine T. solium cysticercosis.

Simple and reliable preparation of immunodiagnostic antigens for Taenia solium cysticercosis.

SUMMARY Cysticercosis caused by infection with the larval stage of Taenia solium is an important cause of neurological disease worldwide and immunodiagnosis is important for the control and elimination of cysticercosis. In the present study, we established a simple and reliable preparation of immunodiagnostic low-molecular-weight antigens (LMWAgs) from T. solium cyst fluids by a cation-exchange chromatography (CEC). Banding patterns of LMWAgs on SDS-PAGE were different between isolates from Ecuador and China. All cysticercosis patient sera and some echinococcosis patient sera recognized both LMWAgs by enzyme-linked immunosorbent assay (ELISA), but sera from healthy persons were not positive. There was no statistical difference in immunodiagnostic performance of LMWAgs prepared from different geographical isolates. These results indicated that these novel immunodiagnostic antigen preparations could contribute the control and prevention of cysticercosis in endemic areas, especially developing countries.

Seroprevalence of toxoplasmosis, toxocariasis and cysticercosis in a rural settlement, São Paulo State, Brazil.

BACKGROUND: The goal of this study was to estimate the seroprevalence of Toxocara spp., Toxoplasma gondii, and Taenia solium metacestode infection and determine some of the associated risk factors for people living in the Dona Carmen settlement, Pontal of Paranapanema, São Paulo, Brazil. METHODS: Serum samples from 194 subjects were tested and participants answered a questionnaire. An enzyme-linked immunosorbent assay (ELISA) system based on Toxocara spp. excretory-secretory antigens obtained from the cultured second-stage larvae of Toxocara canis or vesicular fluid (VF) antigen from Taenia crassiceps metacestode was used to detect anti-Toxocara spp. IgG and IgE and anti-T. solium metacestode, respectively. For cysticercosis, the reactive ELISA samples were assayed by Western blotting using 18 kDa and 14 kDa proteins purified from VF. For T. gondii-specific IgG and IgM antibodies, anti-SAG-1, GRA-1, and GRA-7 epitope specificity was determined by ELISA. RESULTS: Toxoplasma gondii IgG antibodies were found in 102/194 individuals (52·6%) with increased infections in females (P = 0·02) and those with ≤US$300 monthly income (P = 0·01). Positive IgM antibodies were detected in 21/194 individuals (10·8%). Antibodies specific to Toxocara spp. were found in 28/194 subjects (14·4%). All the individuals with Toxocara spp. also had T. gondii-specific IgG antibodies. Taenia solium metacestode antibodies were detected in 11 subjects (5·7%), but none were reactive based on Western blotting. CONCLUSION: In spite of environmental, educational, and socioeconomic factors favoring parasite infection, the seropositivity rates of T. gondii, Toxocara spp., and T. solium metacestode-specific IgG antibodies are similar to the rates found in studies conducted in different populations in Brazil.

Relationship between serum antibodies and Taenia solium larvae burden in pigs raised in field conditions.

BACKGROUND: Serological tests have been used for the diagnosis of Taenia solium infection in pigs. However, those serological results do not necessarily correlate with the actual infection burden after performing pig necropsy. This study aimed to evaluate the Electro Immuno Transfer Blot (EITB) seropositivity with infection burden in naturally infected pigs. METHODOLOGY/PRINCIPAL FINDINGS: In an endemic area of Peru, 476 pigs were sampled. Seroprevalence was 60.5 ± 4.5% with a statistically higher proportion of positive older pigs (>8 months) than young pigs. The logistic model showed that pigs >8 month of age were 2.5 times more likely to be EITB-positive than ≤ 8 months. A subset of 84 seropositive pigs were necropsied, with 45.2% (38/84) positive to 1-2 bands, 46.4% (39/84) to 3 bands, and 8.3% (7/84) to 4+ bands. 41 out of 84 positive pigs were negative to necropsy (48.8%) and 43 (51%) had one or more cysts (positive predictive value). Older pigs showed more moderate and heavy infection burdens compared to younger pigs. In general, regardless of the age of the pig, the probability of having more cysts (parasite burden) increases proportionally with the number of EITB bands. CONCLUSIONS/SIGNIFICANCE: The probability of being necropsy-positive increased with the number of bands, and age. Therefore, the EITB is a measure of exposure rather than a test to determine the real prevalence of cysticercosis infection.

Sex-associated expression of co-stimulatory molecules CD80, CD86, and accessory molecules, PDL-1, PDL-2 and MHC-II, in F480+ macrophages during murine cysticercosis.

Macrophages are critically involved in the interaction between T. crassiceps and the murine host immune system. Also, a strong gender-associated susceptibility to murine cysticercosis has been reported. Here, we examined the sex-associated expression of molecules MHC-II, CD80, CD86, PD-L1, and PD-L2 on peritoneal F4/80(hi) macrophages of BALB/c mice infected with Taenia crassiceps. Peritoneal macrophages from both sexes of mice were exposed to T. crassiceps total extract (TcEx). BALB/c Females mice recruit higher number of macrophages to the peritoneum. Macrophages from infected animals show increased expression of PDL2 and CD80 that was dependent from the sex of the host. These findings suggest that macrophage recruitment at early time points during T. crassiceps infection is a possible mechanism that underlies the differential sex-associated susceptibility displayed by the mouse gender.

Molecular characterization, functional expression, tissue localization and protective potential of a Taenia solium fatty acid-binding protein.

The fatty acid-binding proteins (FABPs) comprise a family of proteins that are widely expressed in animal cells and perform a variety of vital functions. Here, we report the identification, characterization, recombinant expression, tissue localization and protective potential of a Taenia solium FABP (TsFABP1). The TsFABP1 primary structure showed all the conserved residues characteristic of the subfamily iv of the intracellular Lipid-Binding Proteins (iLBPs), including those involved in the binding stabilization of the fatty acid molecule. Through a competitive binding assay we found that TsFABP1 is able to bind at least six different fatty acids with preference toward palmitic and stearic acid, suggesting that TsFABP1 is a member of the iLBP subfamily iv. Immunolocalization assays carried out on larval and adult tissues of four species of taeniids using anti-TsFABP1 hyperimmune sera produced in mice and rabbit, showed intense labeling in the tegument of the spiral canal and in subtegumental cytons of the larvae. These findings suggest that the spiral canal might be a major place for FA uptake in the developing scolex. In contrast, only subtegumental cytons in the adult worms stained positive. We propose that TsFABP1 is involved in the mechanism to mobilize fatty acids between compartments in the extensive syncytial tissue of taeniids. Protection assays carried out in a murine model of cysticercosis showed that subcutaneous immunization with TsFABP1 resulted in about 45% reduction of parasite load against an intraperitoneal challenge with Taenia crassiceps cysts. This reduction in parasite load correlated with the level of cellular and humoral immune responses against TsFABP1, as determined in spleen lymphocyte proliferation and ELISA testing.

Successful immunization of naturally reared pigs against porcine cysticercosis with a recombinant oncosphere antigen vaccine.

Taenia solium causes cysticercosis in pigs and taeniasis and neurocysticercosis in humans. Oncosphere antigens have proven to be effective as vaccines to protect pigs against an experimental infection with T. solium. A pair-matched vaccination trial field, using a combination of two recombinant antigens, TSOL16 and TSOL18, was undertaken in rural villages of Peru to evaluate the efficacy of this vaccine under natural conditions. Pairs of pigs (n=137) comprising one vaccinated and one control animal, were allocated to local villagers. Animals received two vaccinations with 200 µg of each of TSOL16 and TSOL18, plus 5mg Quil-A. Necropsies were performed 7 months after the animals were distributed to the farmers. Vaccination reduced 99.7% and 99.9% (p<0.01) the total number of cysts and the number of viable cysts, respectively. Immunization with the TSOL16-TSOL18 vaccines has the potential to control T. solium transmission in areas where the disease is endemic, reducing the source for tapeworm infections in humans.