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Journal of Clinical Microbiology, January 2000, p. 146-151, Vol. 38, No. 1
Laboratory of Clinical Immunology, Faculty of
Pharmaceutical Sciences,1 and Center
of Neurological Investigation, Faculty of
Medicine,2 University of São Paulo,
São Paulo, SP, Brazil
Received 8 July 1999/Returned for modification 25 August
1999/Accepted 6 October 1999
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
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 (2, 17). Its distribution is universal, with a
frequent occurrence in developing countries in Latin America, Africa,
and India (1, 15, 17, 18). Cases have also been reported in
the United States due to immigration of individuals from areas
where NC is endemic (16).
Diagnosis of NC is based on clinical and epidemiological criteria and
on laboratory methods (neuroimaging and immunological methods).
Clinical diagnosis is impaired by the polymorphic and nonspecific
symptoms of NC, and the detection of anticysticercus antibodies in
cerebrospinal fluid (CSF) represents an important diagnostic element.
The detection of serum antibodies is impaired by cross-reactions with
the agents of parasitoses, such as Echinococcus spp., and
requires the use of purified antigens (20).
The preparation of adequate antigen extracts in sufficient amounts for
the diagnosis of NC is still linked to the detection of swine naturally
infected with T. solium larvae, which are usually reared
under clandestine conditions and which are difficult to locate,
preventing the large-scale production and use of the necessary procedures for specific antigen purification (2, 5, 6, 11, 21,
22).
It would be desirable to have an animal model that is easily maintained
in the laboratory and that can be used as an alternative source of
parasites, and the possibility of achieving such a model arises from
the observation that the Taenia species share common antigens. The ORF strain of T. crassiceps reproduces in an
asexual manner by intraperitoneal passage through female BALB/c mice, representing an important experimental model which, according to
comparative studies with homologous antigens in CSF samples, can be
used for the immunodiagnosis of NC (2, 5, 11, 21, 22).
The immunoblot test has been used for the study of NC, and different
indices of sensitivity and specificity have been observed, depending on
the antigen preparation, on the type and severity of the lesions, and
on the inflammatory reaction surrounding the parasite (6-8, 13,
14, 20, 21). These discordant results should be better explored
in terms of the antigenic epitopes recognized by the host at the local
(CSF) and systemic (serum) levels in order to contribute to the
elucidation of immunopathogenic mechanisms in the host-parasite relationship.
The objective of the present study was to identify the specific
peptides in the T. crassiceps and T. solium
antigen extracts by immunoblotting with serum and CSF samples from
patients with NC and to evaluate the performances of enzyme-linked
immunosorbent assays (ELISAs) and immunoblotting with serum samples
from patients in different evolutionary phases of the disease.
Samples.
A total of 68 paired serum and CSF samples from
patients with NC were studied. The patients were selected according to
the General NC Investigation Protocol of the Hospital of the Faculty of
Medicine, University of São Paulo (approved by the Ethics Committee for the Analysis of Research Projects of the Clinical Director's Office of the Hospital [approval no. 072/97] according to
Resolution 196/96 of the National Health Council, Ministry of Health,
Brasilia, Brazil).
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Specific Taenia crassiceps and Taenia
solium Antigenic Peptides for Neurocysticercosis Immunodiagnosis
Using Serum Samples
ABSTRACT
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
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.
INTRODUCTION
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
MATERIALS AND METHODS
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
Parasites and antigens.
Cysticerci of T. crassiceps (ORF strain) and T. solium, T. crassiceps vesicular fluid antigen (Tcra), and total saline
T. solium antigen (Tso) were obtained by the method of Vaz
et al. (21). Phenylmethylsulfonyl fluoride (Sigma Chemical
Co., St. Louis, Mo.) was added to the antigen extracts at a final
concentration of 0.4 mM, and the preparations were stored at 
70°C.
Immunoenzymatic test (ELISA).
Flat-bottom polystyrene plates
were used (Costar Corporation, Cambridge, Mass.). Skim milk (5%) in
saline solution containing 0.05% Tween 20 was used as a blockade for
2 h at 37°C and as the dilution buffer. Tso and Tcra (10 µg/ml
each), CSF and serum (diluted 1:2 and 1:100, respectively), conjugate
(peroxidase-labeled sheep anti-human immunoglobulin G [IgG; Biolab
Diagnóstica SA, Jaquarepaguá, RJ, Brazil]), and chromogen
substrate (ortho-phenylenediamine [1 g/liter] and
H2O2 [1 ml/liter] in 0.2 M citrate buffer
[pH 5.0]) at volumes of 100 µl/well were used. Incubation was
carried out at 37°C for 1 h for all steps except for those with
the substrate (15 min). The reaction was stopped with 0.5 N
H2SO4 and was read with a plate
spectrophotometer (Diagnostics Pasteur, Strasbourg-Schiltigheim, France) at 492 nm. The absorbance obtained for each test was subtracted from the blank (test with no sample). Determination of the cutoff was
based on the analysis of the diagnostic efficiency according to the
Youden index (24) calculated for the absorbance values of
the control group (mean ± n standard deviation, with
n ranging from 1.16 to +7.0).
Immunoblotting. Tso and Tcra immunoblotting analyses were performed with 64 and 65 CSF samples and 48 and 62 serum samples, respectively, from patients with NC. All of the samples were reactive to the same antigen by ELISA. Serum and CSF samples from group C and serum samples from group OP were also assayed. For analysis of Tcra, six serum samples that were negative by ELISA were also assayed. Positive, negative, and background (with no sample) controls were included in each test.
Tso and Tcra extracts (7 µg/mm) were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) on a 7 to 20% gel gradient (10) and were transferred electrophoretically to 0.22-µm-pore-size nitrocellulose membranes (Millipore Corp., Bedford, Mass.) (19), which were cut into 3 to 4-mm-wide strips. Phosphate-buffered saline (PBS; 0.01 M; pH 7.2; 0.0075 M Na2HPO4, 0.025 M NaH2PO4, and 0.14 M NaCl) containing 0.05% Tween 20 was used for the washes and for the preparation of skim milk. The strips were blocked for 2 h with 5% milk, and the CSF and serum samples were diluted 1:2 and 1:100, respectively, with 1% milk and were incubated for 18 h 4°C. The conjugate used was biotin-labeled goat anti-human IgG and peroxidase-labeled avidin (Cambridge Biotech Co., Mass.), with incubation for 1 h. Antibodies that bound to Tcra were visualized with 0.017% diaminobenzidine and 5% H2O2 in PBS. The chromogen-substrate for Tso blots was 0.05% 4-chloronaphthol predissolved in methanol (1/5 of the volume) and in Tris-buffered saline (0.01 M; pH 7.4; Tris-hydroxymethylaminoethane and 0.15 M NaCl)-0.6% H2O2, which permitted a better identification of the peptides.| |
RESULTS |
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Abstract
Introduction
Materials and Methods
Results
Discussion
References
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ELISA. The ELISA results obtained for CSF and serum samples from patients with NC and in groups C and OP by using Tso and Tcra are presented in Fig. 1. All CSF samples in group C were nonreactive by the ELISAs with Tcra and Tso. Nine (26%) of the 35 group C serum samples were reactive by ELISA: 5 with both antigens, 2 with Tso, and 2 with Tcra. Five (22%) of the 23 group OP serum samples were reactive with both antigens, and 9 (39%) additional samples were reactive only with Tcra. The sensitivity, specificity, and Youden index are presented in Table 1.
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Immunoblotting. In the Tcra immunoblotting assay, 64 (98.5%) CSF samples and 61 (98.0%) serum samples were reactive. In the Tso immunoblotting assay, 62 (96.9%) CSF samples and all serum samples from patients with NC were reactive.
Figures 2 and 3 show the blots obtained with Tcra and Tso, respectively, and Table 2 presents the peptides that were reactive in the blot with the samples from patients with NC and in groups C and OP.
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DISCUSSION |
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Abstract
Introduction
Materials and Methods
Results
Discussion
References
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The objective of the present investigation was to study serum samples, which can be obtained in a less invasive manner than that required for retrieval of CSF, for the diagnosis of NC and for seroepidemiological studies for the mapping of areas of Brazil where NC is endemic. Thus, for the validation of the serologic tests developed in the present study, we used as a reference the results obtained with paired CSF samples from patients with NC.
The host-parasite biological interactions involved in NC are complex in view of the different stages of parasite evolution and of the individual variations that interfere with the host response (16), justifying the importance of the study of immunodiagnostic tests with patients with different evolutionary stages of the disease. In addition, adequate antigen extracts are difficult to obtain in sufficient amounts for immunologic tests because of the need to obtain swine naturally infected with T. solium larvae. Furthermore, the removal of individual cysticerci from infected tissues is cumbersome and time-consuming.
The major advantages of the use of the heterologous antigen Tcra are the unlimited source of cysticerci, the minimal cost of the antigen due to its production in the laboratory, and the easier extraction of the antigen from the parasites. The tests with the Tcra have shown good reproducibilities with different lots of antigen, as evaluated by the peptide pattern by SDS-PAGE and by the results for the positive and negative controls used in each assay.
The search for IgG antibodies in CSF samples by ELISA has revealed sensitivities of 94.1 and 95.6% for Tso and Tcra, respectively, and 100.0% specificity for both antigens, with no significant difference (P > 0.30). Similar results were reported by other investigators who used Tcra (6, 11).
The ELISAs used to search for serum antibodies to Tso and Tcra showed sensitivities of 70.6 and 91.2% (P < 0.001), respectively, and specificities of 80.0% for both antigens (Table 1). These differences can be explained by the different evolutionary phases of NC and by the high incidence of organisms that cause other parasitoses and that cross-react with T. solium. In a study with serum, Espinoza et al. (3) obtained better results, i.e., 80% sensitivity and 96% specificity with antigen B and 85% sensitivity and 100% specificity with the crude antigen of T. solium. The loss of the antigenic components of vesicular fluid in the preparation of Tso may have led to these discordant results due to the lower sensitivity of our crude antigen. Using vesicular fluid of T. crassiceps and T. solium by ELISA, Kunz et al. (9) detected antibodies in the 14 serum samples analyzed and reported a higher-intensity reading with the T. solium antigen, as was also observed in the present study (Fig. 1). Gottstein et al. (7) observed a lower specificity (49%) in an ELISA with total T. solium antigen, with cross-reactivity with sera from patients with intestinal parasitoses, which have high rates of occurrence in Brazil. Although the specificities observed here with Tso and Tcra were higher, there was a 20% rate of false-positive results which may have been due to these other infections.
Of the 6 serum samples from patients with NC that were negative by the Tcra ELISA, 4 were from patients who presented with calcifications in the imaging examinations, whereas for Tso, 8 of the 20 negative samples had calcifications, and 5 were from patients with intact cysts or normal imaging examinations. These data show a higher sensitivity of Tcra for the detection of antibodies in the sera of patients who did not present with signs of an inflammatory process and even in those who were in the calcification phase. In contrast, some investigators have reported the lower sensitivities of immunologic tests with both CSF and serum during the calcification phase due to the lower antibody concentration, regardless of the antigen used (9, 13, 23).
The lower sensitivity of the ELISA with Tso for the detection of antibodies in serum compared to the sensitivity for the detection of antibodies in CSF may have been due to compartmentalization of the infection and to intrathecal synthesis of antibodies in response to the parasite (4), as well as to the presence of different serum components that might interfere with and/or block the reactivity with specific antigens and that are absent from CSF. The purification of specific peptides and their use at appropriate concentrations should improve the efficiency of the test but would require large volumes of antigen (20), a procedure that would be more feasible only with the Tcra model.
The presence of one or more peptides of 23, 39, 85 to 77, and 97 kDa
in the blot was Tso specific and confirmed NC. We observed reactivity
with one or more of these peptides with all 48 ELISA-reactive serum
samples. Of the 64 ELISA-reactive CSF samples analyzed, 2 were not
reactive by immunoblotting and, coincidentally, were those that had
absorbances close to the cutoff for the ELISA, and these two patients
had normal imaging examinations or intact cysts. Another CSF sample was
reactive by immunoblotting only with the 50- to 46-kDa peptide, which
was also reactive with CSF samples from patients with NC (94%), serum
samples from patients with NC (69%), and samples in groups C (71%)
and OP (70%). This patient was in the calcification phase, and his CSF
was also reactive in the Tcra blot (reactive with the 19- to 13-kDa
peptide). The detection of antibodies in CSF always seems to be
specific unless immunoglobulins cross the blood-brain barrier. The
peptide of 50 to 46 kDa may show cross-reactivity in serum, but it may
also be present in the cysticercus.
For serum samples tested by immunoblotting with Tso, Grogl et al. (8) suggested that peptides of 64, 53, and 32 to 30 kDa are of those that should be chosen for use in the development of immunologic tests, while Gottstein et al. (7) showed that the 26-kDa and/or 8-kDa fractions of T. solium were specific. Tsang et al. (20), using purified antigen of T. solium cysticerci, reported that glycoprotein bands of 50, 42 to 39, 24, 21, 18, 14, and 13 kDa confirmed the diagnosis of NC.
Michault et al. (13) demonstrated that only serum samples from patients with NC in the active phase reacted with the 14-kDa band. Our results confirm the specificity of this peptide in Tso, but we observed no association with the evolutionary phase of NC, with the peptide being reactive with 50% of the sera from patients with degenerating cysts and 43% of the sera from patients with calcified cysts.
For Tcra, we may consider the presence of at least one of the peptides
of 62, 74, 109, 121, and 131 kDa to be specific and confirmatory for
NC. Of the 65 ELISA-reactive CSF samples from patients with NC, only 1 was negative by immunoblotting. This sample had an absorbance close to
the cutoff for the ELISA, and the patient presented with intact cysts
with no inflammatory response. Of the 62 ELISA-reactive serum samples
tested, 1 was reactive only with peptides that reacted with samples in
group C (146- and 96-kDa peptides) and group OP (96- and 65-kDa
peptides). The 96-kDa peptide was reactive with 82% of the serum and
CSF samples from patients with NC and the sera in groups C (46%) and
OP (35%). The 65-kDa peptide, which was present in 87% of the sera
from patients with NC, was recognized by the sera in groups C (37%) and OP (56%). It is possible that the 96- and 65-kDa peptides detected
here are absolutely nonspecific in view of the similar frequencies at
which they appeared in all groups. On the other hand, the 146-kDa
peptide, which was present in 35% of the serum samples from patients
with NC, was observed only in samples in group OP (22%) and seemed to
be more cross-reactive than nonspecific.
There are few reports of the use of immunoblotting with Tcra only with CSF for the detection of NC. In 1995, Garcia et al. (6), by immunoblotting CSF samples from patients with NC using vesicular fluid antigen of T. crassiceps and considering the 110- to 45-kDa peptides to be specific, reported that the assay had 93% sensitivity and 98% specificity. Recently, Vaz et al. (21), in a study of CSF, observed the immunodominance of the 72- to 68-, 95- to 92-, and several >100-kDa peptides of vesicular fluid antigen of T. crassiceps without detecting peptides of <20 kDa, possibly due to methodologic differences, as pointed out by Tsang et al. (20).
The results obtained with Tso and Tcra in our tests support the idea that the parasites share important epitopes and are present at concentrations sufficient for use in the immunodiagnosis of NC, except with serum, for which Tcra had a significant advantage (P < 0.001).
We suggest that ELISA with Tcra can be applied to serum samples for the screening of NC (91.2% sensitivity), especially for patients with calcifications and reduced immunoinflammatory responses. We believe that Tcra, although heterologous, has these advantages because it is rich in vesicular fluid components, which include soluble secretion and excretion antigens. These antigens are also present in T. solium cysticerci but at lower concentrations compared to those in the membrane and scolex components due to the rupture of vesicles during the process of parasite removal from swine tissue. Thus, for cysticerci of T. solium, the use of antigen purification procedures should be necessary (20).
Although no significant difference (P > 0.10) was observed between ELISA and immunoblotting, it is necessary to use Tcra immunoblotting for the confirmation of the results for sera that are reactive by ELISA. The purification of immunodominant peptides in Tcra (e.g., 19- to 13-kDa peptides) and its use at adequate concentrations in ELISA may facilitate seroepidemiologic studies with humans and swine, at reduced cost, for the evaluation of the real situation of the taeniasis-cysticercosis situation in Brazil.
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ACKNOWLEDGMENTS |
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This research was supported by FAPESP (grant 96-7679-1) and by a CAPES fellowship (to Ednéia Casagranda Bueno).
We are indebted to Aluízio B. B. Machado, Antônio Walter Ferreira, and Hermínia Y. Kanamura for providing some samples, to Biolab-Meuriex for providing the conjugate used in the ELISA, to Vitória Bartoly for help with CSF collection, and to Paulo M. Nakamura and Rute K. C. Chang for technical assistance.
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FOOTNOTES |
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* Corresponding author. Mailing address: Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, Av. Lineu Prestes, 580, Bloco 17, Laboratório de Immunologia Clínica, CEP 05508-900, São Paulo, SP, Brazil. Phone: 55-11-8183638. Fax: 55-11-8132197. E-mail: ecbueno{at}usp.br.
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REFERENCES |
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Abstract
Introduction
Materials and Methods
Results
Discussion
References
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| 1. | Agapejev, S. 1996. Epidemiology of neurocysticercosis in Brazil. Rev. Inst. Med. Trop. São Paulo 38:207-216[Medline]. |
| 2. | Andrade, A. P., A. J. Vaz, P. M. Nakamura, V. S. E. B. Palou, R. A. F. Cunha, and A. W. Ferreira. 1996. Immunoperoxidase for the detection of antibodies in cerebrospinal fluid in neurocysticercosis: use of Cysticercus cellulosae and Cysticercus longicollis particles fixed on microscopy slides. Rev. Inst. Med. Trop. São Paulo 38:259-263[Medline]. |
| 3. |
Espinoza, B.,
G. R. Palacios,
A. Tovar,
M. A. Sandoval,
A. Plancarte, and A. Flisser.
1986.
Characterization by enzyme-linked immunosorbent assay of the humoral immune response in patients with neurocysticercosis and its application in immunodiagnosis.
J. Clin. Microbiol.
24:536-541 |
| 4. |
Estanol, B.,
H. Guárez,
M. C. Irigoyen,
D. González-Barranco, and T. Corona.
1989.
Humoral immune response in patients with cerebral parenchymal cysticercosis treated with praziquantel.
J. Neurol. Neurosurg. Psychiatr.
52:254-257 |
| 5. | Ferreira, A. P., A. J. Vaz, P. M. Nakamura, A. T. Sasaki, A. W. Ferreira, and J. A. Livramento. 1997. Hemagglutination test for the diagnosis of human neurocysticercosis: development of a stable reagent using homologous and heterologous antigens. Rev. Inst. Med. Trop. São Paulo 39:29-33[Medline]. |
| 6. | Garcia, E., G. Ordonez, and J. Sotelo. 1995. Antigens from Taenia crassiceps used in complement fixation, enzyme-linked immunosorbent assay, and Western blot (immunoblot) for diagnosis of neurocysticercosis. J. Clin. Microbiol. 33:3324-3325[Abstract]. |
| 7. | Gottstein, B., D. Zini, and P. M. Schantz. 1987. Species-specific immunodiagnosis of Taenia solium cystecercosis by ELISA and immunoblotting. Trop. Med. Parasitol. 38:299-303[Medline]. |
| 8. | Grogl, M., J. J. Estrada, G. MacDonald, and R. E. Kuhn. 1985. Antigen-antibody analysis in neurocysticercosis. J. Parasitol. 71:433-442[CrossRef][Medline]. |
| 9. | Kunz, J., B. Kalinna, V. Watschke, and E. Geyer. 1989. Taenia crassiceps metacestode vesicular fluid antigens shared with the Taenia solium larval stage and reactive with serum antibodies from patients with neurocysticercosis. Zentbl. Bakteriol. Parasitenkd. Infektkrankh. Hyg. Abt. 1 Orig. 271:510-520. |
| 10. | Laemmli, U. K. 1970. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 227:680-685[CrossRef][Medline]. |
| 11. | Larralde, C., J. Sotelo, R. M. Montoya, G. Palencia, A. Padilla, T. Govezensky, M. L. Diaz, and E. Sciutto. 1990. Immunodiagnosis of human cysticercosis in cerebrospinal fluid. Antigens from murine Taenia crassiceps cysticerci effectively substitute those from porcine Taenia solium. Arch. Pathol. Lab. Med. 114:926-928[Medline]. |
| 12. | Machado, L. R., J. P. S. Nobrega, N. G. Barros, J. A. Livramento, L. A. Bacheschi, and A. Spina-França. 1990. Computed tomography in neurocysticercosis. A 10-year long evolution analysis of 100 patients with an appraisal of a new classification. Arq. Neuro-Psiquiatr. 48:414-418[Medline]. |
| 13. | Michault, A., B. Rivière, P. Fressy, J. P. Laporte, G. Bertil, and C. Mignard. 1990. Apport de l'enzyme-linked immunoelectrotransfer blot assay au diagnostic de la neurocysticercose humaine. Pathol. Biol. 38:119-125[Medline]. |
| 14. | Michel, P., A. Michault, J. C. Gruel, and P. Coulanges. 1990. Le serodiagnostic de la cysticercose par ELISA et Western blot. Son intérêt et ses limites à Madagascar. Arch. Inst. Pasteur Madagascar 57:115-142[Medline]. |
| 15. | Sarti, E., A. Flisser, P. M. Schantz, M. Gleizer, M. Loya, A. Plancarte, G. Avila, J. Allan, P. Craig, M. Bronfaman, and P. Wijeyaratne. 1997. Development and evaluation of a health education intervention against Taenia solium in a rural community in Mexico. Am. J. Trop. Med. Hyg. 56:127-132. |
| 16. | Schantz, P. M., A. C. Moore, J. L. Munöz, B. J. Hartman, J. A. Schaefer, A. M. Aron, D. Persuad, E. Sarti, M. Wilson, and A. Flisser. 1992. Neurocysticercosis in an Orthodox Jewish community in New York City. N. Engl. J. Med. 327:692-695[Abstract]. |
| 17. | Shasha, W., and M. D. Pammenter. 1991. Sero-epidemiological studies of cysticercosis in school children from two rural areas of Transkei, South Africa. Ann. Trop. Med. Parasitol. 85:349-355[Medline]. |
| 18. | Singh, G. 1997. Neurocysticercosos in South-Central America and the Indian subcontinent. A comparative evaluation. Arq. Neuropsiquiatr. 55(Suppl. 3-A):349-356[Medline]. |
| 19. |
Towbin, H.,
T. Staehelin, and J. Gordon.
1979.
Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications.
Proc. Natl. Acad. Sci. USA
76:4350-4352 |
| 20. | Tsang, V. C. W., J. A. Brand, and A. E. Boyer. 1989. An enzyme-linked immunoelectrotransfer blot assay and glycoprotein antigens for diagnosing human cysticercosis (Taenia solim). J. Infect. Dis. 159:50-59[Medline]. |
| 21. | Vaz, A. J., C. M. Nunes, R. M. F. Piazza, J. A. Livramento, M. V. Silva, P. M. Nakamura, and A. W. Ferreira. 1997. Immunoblot with cerebrospinal fluid from patients with neurocysticercosis using antigen from cysticerci of Taenia solium and Taenia crassiceps. Am. J. Trop. Med. Hyg. 57:354-357. |
| 22. | Vaz, A. J., P. M. Nakamura, C. C. Barreto, A. W. Ferreira, J. A. Livramento, and A. B. B. Machado. 1997. Immunodiagnosis of human neurocysticercosis: use of heterologous antigenic particles (Cysticercus longicollis) in indirect immunofluorescence test. Serodiagn. Immunother. Infect. Dis. 8:157-161. |
| 23. | Wilson, M., R. T. Bryan, J. A. Fried, D. A. Ware, P. M. Schantz, J. B. Pilcher, and V. C. W. Tsang. 1991. Clinical evaluation of the cysticercosis enzyme-linked immunoelectrotransfer blot in patients with neurocysticercosis. J. Infect. Dis. 164:1007-1009[Medline]. |
| 24. | Youden, D. 1950. Index for rating diagnostic test. Cancer 3:32-35[CrossRef][Medline]. |
Journal of Clinical Microbiology, January 2000, p. 146-151, Vol. 38, No. 1
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Copyright © 2000, American Society for Microbiology. All rights reserved.
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