Diagnosis of human toxoplasmosis by a dot enzyme-linked immunosorbent assay

Elsaid, Mohamed Mohamed Anwar; Bahia, Maria Terezinha; Machado-Coelho, George Luiz; Vitor, Ricardo Wagner de Almeida

doi:10.1590/S0036-46651995000200005

Abstracts

A Dot enzyme-linked immunosorbent assay (Dot-ELISA) was standardized and evaluated for the serodiagnosis of human toxoplasmosis. Out of 538 serum samples tested by the immunofluorescence test for toxoplasmosis (IFAT-IgG) as reference test, 183 (34%) were positive at cut off 1:16 and 192 (36%) were positive for Dot-ELISA-IgG at cut-off 1:256. For Dot-ELISA, co-positivity was 0.94, co-negativity 0.94 and concordance 0.88 in relation to IFAT-IgG. These results suggest the usefulness of Dot-ELISA (cut-off titer of 1:256) for the serodiagnosis of human toxoplasmosis. The main advantage of this technique is simplicity, positive test can be visually identified (colored precipitate). It does not require a special equipment and it can be used as a qualitative test to screen large numbers of samples or as a quantitative assay to determine end-point titration of individual sera.

Human toxoplasmosis; Dot-ELISA; Serodiagnosis

O Dot-ELISA foi padronizado e avaliado para o imunodiagnóstico da toxoplasmose humana. Entre 538 amostras testadas pela reação de Imunofluorescência Indireta (teste de referência) 183 foram positivas considerando-se os soros reagentes nas diluições > 1:16 (34%). Utilizando a diluição 1:256 como título discriminante para o Dot-ELISA, foram observados 192 soros positivos (36%). A comparação entre as duas técnicas mostrou os seguintes resultados: co-positividade = 0,94, co-negatividade = 0,94 e youden = 0,88. Estes resultados mostram que o Dot-ELISA pode ser aplicado no imunodiagnóstico da toxoplasmose humana utilizando o título discriminante de 1:256. Entre as principais vantagens desta técnica podemos citar sua simplicidade, leitura visual sem uso de aparelho e utilização como teste qualitativo em levantamentos epidemiológicos ou como teste quantitativo para titulação de soros.

DIAGNOSTIC STUDIES

Diagnosis of human toxoplasmosis by a dot enzyme-linked immunosorbent assay

Diagnóstico da toxoplasmose humana através de um tese imunoenzimático Dot-ELISA

Mohamed Mohamed Anwar Elsaid^I; Maria Terezinha Bahia^II; George Luiz Machado-Coelho^II; Ricardo Wagner de Almeida Vitor^I

^IDepartamento de Parasitologia, ICB, UFMG, Belo Horizonte, MG., Brasil

^IIUniversidade Federal de Ouro Preto, MG, Brasil

^{Correspondence to} Correspondence to: Dr. Ricardo Wagner de Almeida Vitor Departamento de Parasitologia, ICB, UFMG Caixa Postal 468, 31270-901, Belo Horizonte, MG, Brasil

SUMMARY

A Dot enzyme-linked immunosorbent assay (Dot-ELISA) was standardized and evaluated for the serodiagnosis of human toxoplasmosis. Out of 538 serum samples tested by the immunofluorescence test for toxoplasmosis (IFAT-IgG) as reference test, 183 (34%) were positive at cut off 1:16 and 192 (36%) were positive for Dot-ELISA-IgG at cut-off 1:256. For Dot-ELISA, co-positivity was 0.94, co-negativity 0.94 and concordance 0.88 in relation to IFAT-IgG. These results suggest the usefulness of Dot-ELISA (cut-off titer of 1:256) for the serodiagnosis of human toxoplasmosis. The main advantage of this technique is simplicity, positive test can be visually identified (colored precipitate). It does not require a special equipment and it can be used as a qualitative test to screen large numbers of samples or as a quantitative assay to determine end-point titration of individual sera.

Keywords: Human toxoplasmosis; Dot-ELISA; Serodiagnosis.

RESUMO

O Dot-ELISA foi padronizado e avaliado para o imunodiagnóstico da toxoplasmose humana. Entre 538 amostras testadas pela reação de Imunofluorescência Indireta (teste de referência) 183 foram positivas considerando-se os soros reagentes nas diluições > 1:16 (34%). Utilizando a diluição 1:256 como título discriminante para o Dot-ELISA, foram observados 192 soros positivos (36%). A comparação entre as duas técnicas mostrou os seguintes resultados: co-positividade = 0,94, co-negatividade = 0,94 e youden = 0,88. Estes resultados mostram que o Dot-ELISA pode ser aplicado no imunodiagnóstico da toxoplasmose humana utilizando o título discriminante de 1:256. Entre as principais vantagens desta técnica podemos citar sua simplicidade, leitura visual sem uso de aparelho e utilização como teste qualitativo em levantamentos epidemiológicos ou como teste quantitativo para titulação de soros.

Full text available only in PDF format.

Texto completo disponível apenas em PDF.

ACKNOWLEDGEMENTS

To Rosalida Estevam Nazar Lopes and José Luiz de Faria for technical help and Prof. Paul Williams for reviewing the manuscript.

Recebido para publicação 19/08/1994.

Aceito para publicação em 15/12/1994.

Supported by PRPQ-UFMG.

1. ARAUJO, F.G. - A method for demonstration of antibodies to Trypanosoma cruzi by using antigen-coated nitrocellulose paper strips. Amer. J. trop. Med. Hyg., 34: 242-245, 1985.
2. ARMITAGE, P. - Statistical method in medical research. London, Blackwell Scientific Publications, 1973.
3. BAHIA, M.T.; VITOR, R.W.; CALDAS, R.P.; ANTUNES, C.M. & CHIARI, C.A. - Diagnosis of caprine toxoplasmosis by a dot Enzyme-Linked Immunosorbent Assay. Arq. bras. Med. vet. Zoot., 45: 173-183, 1993.
4. BUCK, A.A. & GART, J.J. - Comparison of a screening test and a reference test in epidemiologic studies. I. Indices of agreement and their relation to prevalence. Amer. J. Epidem., 83: 586-592, 1966.
5. BURT, S.M.; CARTER, T.J.N. & KRICK, L.J. - Thermal characteristics of microtiter plates used in immunological assay. J. Immunol. Meth., 31: 231-236, 1979.
6. CAMARGO, M.E. - Estudo comparativo das reaçőes de Sabin Feldman e de imunofluorescęncia indireta para a Toxoplasmose em 1000 soros humanos, comportamento anômalo de alguns soros. Rev. Inst. Adolfo Lutz., 24: 1-26, 1964.
7. CAMARGO, M.E.; MOURA, M.E.G. & LESER, P.G. - Toxoplasmosis serology: an efficient hemagglutination procedure to detect IgG and IgM antibodies. Rev. Inst. Med. trop. S. Paulo, 31: 279-285, 1989.
8. CHESSUM, B.S. & DENMARK, J.R. - Inconstant ELISA. Lancet, 1: 161, 1978.
9. HAWKES, R.; NIDAY, E. & GORDON, J. - A dot immunobinding assay for monoclonal and other antibodies. Analyt. Biochem., 119: 142-147, 1982.
10. JACOBS, L. & LUNDE, M.A. - Hemagglutination test for toxoplasmosis, J. Parasit., 43: 308-314, 1957.
11. KENT, J.F. & FILE, E.H. - Precise standardization of reagents for complement fixation. Amer. J. trop. Med. Hyg., 12: 103-116, 1963.
12. KRICKA, L.J.; CARTER, T.J.N.; BURT, S.M. et al. - Variability in the adsorption properties of microtiter plates used as solid supports in enzyme immunoassay. Clin. Chem., 26: 741-744, 1980.
13. LIN, T.M. & HALBERT, S.P. - Rapid dot enzyme immunoassay for the detection of antibodies to cytomegalovirus. J. clin. Microbiol., 24: 7-11, 1986.
14. LOWRY, O.H.; ROSEBROUGH, N.J.; FARR, A.L. & RANDALL, R.J. - Protein measurement with the folin phenol reagent. J. biol. Chem., 193: 265-275, 1951.
15. NAOT, Y. & REMINGTON, J.S. - An enzyme-linked immunosorbent assay for detection of IgM antibodies to Toxoplasma gondii: use for diagnosis of acute acquired toxoplasmosis. J. infect. Dis., 142: 757-766, 1980.
16. PAPPAS, M.G. - New test may improve Third World health care. Clin. Chem. News, 13: 5, 1987.
17. PAPPAS, M.G.; LUNDE, M.N.; HAJKOWSKI, R. & McMAHON, J. - Determination of IgM and IgG antibodies to Toxoplasma using the IFA test, ELISA and Dot-ELISA procedures. Vet. Parasit., 20: 31-42, 1986.
18. PAPPAS, M.G.; SCHANTZ, P.M.; CANNON, L.T. & WAHLQUIST, S.P. - Dot-ELISA for the rapid serodiagnosis of human hydatid disease. Diagn. Immunol., 4: 271-276, 1986.
19. SABIN, A.B. & FELDMAN, H.A. - Dyes as micochemical indicators of a new immunity phenomenon affecting a protozoan parasite (Toxoplasma). Science, 108: 660-663, 1948.
20. SNEDECOR, G.W. & COCHRAN, W.G. - Statistical methods. 6. ed. Ames, The Iowa State University Press, 1972.
21. VAZ, A.J. & FERREIRA, A.W. - Imunodiagnóstico da neurocisticercose: teste imunoenzimático com antígenos quimicamente ligados a suportes para pesquisa de anticorpos em soro e líquido cefalorraquiano. Rev. Inst. Med. trop. S. Paulo, 30: 1-10, 1988.
22. VOLLER, A.; BIDWELL, D.E. & BARTLETT, A. - Enzyme immunoassays in diagnostic medicine: theory and practice. Bull. Wld. Hlth. Org., 53: 55-65, 1976.
23. YOUDEN, W.J. - Index for rating diagnostic test. Cancer, 3: 32-35, 1950.
24. ZIMMERMAN, G.L.; NELSON, M.J. & CLARK, C.R.B. - Diagnosis of ovine fascioliasis by a dot enzyme-linked immunosorbent assay: a rapid microdiagnostic technique. Amer. J. vet. Res., 46: 1513-1515, 1985.

Correspondence to:

Dr. Ricardo Wagner de Almeida Vitor

Departamento de Parasitologia, ICB, UFMG

Caixa Postal 468, 31270-901, Belo Horizonte, MG, Brasil

Publication Dates

Publication in this collection
22 Feb 2007
Date of issue
Apr 1995

History

Accepted
15 Dec 1994
Received
19 Aug 1994

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

[1] 1. ARAUJO, F.G. - A method for demonstration of antibodies to Trypanosoma cruzi by using antigen-coated nitrocellulose paper strips. Amer. J. trop. Med. Hyg., 34: 242-245, 1985.

[2] 2. ARMITAGE, P. - Statistical method in medical research. London, Blackwell Scientific Publications, 1973.

[3] 3. BAHIA, M.T.; VITOR, R.W.; CALDAS, R.P.; ANTUNES, C.M. & CHIARI, C.A. - Diagnosis of caprine toxoplasmosis by a dot Enzyme-Linked Immunosorbent Assay. Arq. bras. Med. vet. Zoot., 45: 173-183, 1993.

[4] 4. BUCK, A.A. & GART, J.J. - Comparison of a screening test and a reference test in epidemiologic studies. I. Indices of agreement and their relation to prevalence. Amer. J. Epidem., 83: 586-592, 1966.

[5] 5. BURT, S.M.; CARTER, T.J.N. & KRICK, L.J. - Thermal characteristics of microtiter plates used in immunological assay. J. Immunol. Meth., 31: 231-236, 1979.

[6] 6. CAMARGO, M.E. - Estudo comparativo das reaçőes de Sabin Feldman e de imunofluorescęncia indireta para a Toxoplasmose em 1000 soros humanos, comportamento anômalo de alguns soros. Rev. Inst. Adolfo Lutz., 24: 1-26, 1964.

[7] 7. CAMARGO, M.E.; MOURA, M.E.G. & LESER, P.G. - Toxoplasmosis serology: an efficient hemagglutination procedure to detect IgG and IgM antibodies. Rev. Inst. Med. trop. S. Paulo, 31: 279-285, 1989.

[8] 8. CHESSUM, B.S. & DENMARK, J.R. - Inconstant ELISA. Lancet, 1: 161, 1978.

[9] 9. HAWKES, R.; NIDAY, E. & GORDON, J. - A dot immunobinding assay for monoclonal and other antibodies. Analyt. Biochem., 119: 142-147, 1982.

[10] 10. JACOBS, L. & LUNDE, M.A. - Hemagglutination test for toxoplasmosis, J. Parasit., 43: 308-314, 1957.

[11] 11. KENT, J.F. & FILE, E.H. - Precise standardization of reagents for complement fixation. Amer. J. trop. Med. Hyg., 12: 103-116, 1963.

[12] 12. KRICKA, L.J.; CARTER, T.J.N.; BURT, S.M. et al. - Variability in the adsorption properties of microtiter plates used as solid supports in enzyme immunoassay. Clin. Chem., 26: 741-744, 1980.

[13] 13. LIN, T.M. & HALBERT, S.P. - Rapid dot enzyme immunoassay for the detection of antibodies to cytomegalovirus. J. clin. Microbiol., 24: 7-11, 1986.

[14] 14. LOWRY, O.H.; ROSEBROUGH, N.J.; FARR, A.L. & RANDALL, R.J. - Protein measurement with the folin phenol reagent. J. biol. Chem., 193: 265-275, 1951.

[15] 15. NAOT, Y. & REMINGTON, J.S. - An enzyme-linked immunosorbent assay for detection of IgM antibodies to Toxoplasma gondii: use for diagnosis of acute acquired toxoplasmosis. J. infect. Dis., 142: 757-766, 1980.

[16] 16. PAPPAS, M.G. - New test may improve Third World health care. Clin. Chem. News, 13: 5, 1987.

[17] 17. PAPPAS, M.G.; LUNDE, M.N.; HAJKOWSKI, R. & McMAHON, J. - Determination of IgM and IgG antibodies to Toxoplasma using the IFA test, ELISA and Dot-ELISA procedures. Vet. Parasit., 20: 31-42, 1986.

[18] 18. PAPPAS, M.G.; SCHANTZ, P.M.; CANNON, L.T. & WAHLQUIST, S.P. - Dot-ELISA for the rapid serodiagnosis of human hydatid disease. Diagn. Immunol., 4: 271-276, 1986.

[19] 19. SABIN, A.B. & FELDMAN, H.A. - Dyes as micochemical indicators of a new immunity phenomenon affecting a protozoan parasite (Toxoplasma). Science, 108: 660-663, 1948.

[20] 20. SNEDECOR, G.W. & COCHRAN, W.G. - Statistical methods. 6. ed. Ames, The Iowa State University Press, 1972.

[21] 21. VAZ, A.J. & FERREIRA, A.W. - Imunodiagnóstico da neurocisticercose: teste imunoenzimático com antígenos quimicamente ligados a suportes para pesquisa de anticorpos em soro e líquido cefalorraquiano. Rev. Inst. Med. trop. S. Paulo, 30: 1-10, 1988.

[22] 22. VOLLER, A.; BIDWELL, D.E. & BARTLETT, A. - Enzyme immunoassays in diagnostic medicine: theory and practice. Bull. Wld. Hlth. Org., 53: 55-65, 1976.

[23] 23. YOUDEN, W.J. - Index for rating diagnostic test. Cancer, 3: 32-35, 1950.

[24] 24. ZIMMERMAN, G.L.; NELSON, M.J. & CLARK, C.R.B. - Diagnosis of ovine fascioliasis by a dot enzyme-linked immunosorbent assay: a rapid microdiagnostic technique. Amer. J. vet. Res., 46: 1513-1515, 1985.