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Revista do Instituto de Medicina Tropical de São Paulo

On-line version ISSN 1678-9946

Rev. Inst. Med. trop. S. Paulo vol.28 no.1 São Paulo Jan./Feb. 1986

http://dx.doi.org/10.1590/S0036-46651986000100002 

ARTIGOS ORIGINAIS

 

Pesquisa de anticorpos IgM anti-Toxoplasma gondii por meio de técnica imunoenzimática reversa

 

Reverse IgM enzyme-linked immunosorbent assay (Reverse IgM-ELISA) for toxoplasmosis serodiagnosis

 

 

José Roberto Mineo; Mário Endsfeldz Camargo; Antonio Walter Ferreira; Gastão Almeida

Departamento de Ciências Fundamentais para a saúde, Universidade Federal de Uberlândia

Presente endereço

 

 


RESUMO

Um teste imunoenzimático reverso foi padronizado utilizando-se como fase sólida, microplacas de polivinil sensibilizadas com anticorpos anti-IgM.7 Estas foram incubadas seqüencialmente com alíquotas de soros de pacientes com suspeita de toxoplasmose aguda, antígeno solúvel de Toxoplasma gondii, conjugado peroxidase F (ab')2 anti-toxoplasma e substrato enzimático. A atividade enzimática foi determinada por leitura espectrofotométrica, considerando-se como títulos dos soros a máxima diluição fornecendo valores de absorbância maiores que os obtidos com a menor diluição do soro padrão não-reativo. Em 69 amostras de soros de pacientes com toxoplasmose aguda, a média geométrica dos títulos no teste ELISA-Reverso IgM foi superior à de todos os outros testes para anticorpos IgM, não se observando resultados negativos falsos devidos a altos títulos de IgG específica. Não foi encontrada, também, reatividade cruzada em nenhuma das 104 amostras de soros de pacientes com outras patologias, inclusive em amostras contendo fator reumatóide IgM.

Unitermos: Toxoplasmose — Diagnóstico — Sorologia — Imunoenzimologia reversa.


SUMMARY

A Reverse IgM enzyme — linked immunosorbent assay (Reverse-IgM ELISA) was described in which polyvinyl microplates were sensitized with anti-immunoglobulin M (IgM) antibodies and then sequentially allowed to react with patient's serum, Toxoplasma gondii soluble antigen, peroxidase — labeled specific F(ab')2 fragment and substrat. Measurement of activity of the solid phase bound enzyme conjugate was done by spectrofotometric reading of the final developed color. In a group of 69 sera samples from individuals with recently acquired toxoplasmosis, Reverse-IgM ELISA was positive in every case, showing higher geometric mean titer than others conventional serological tests. Furthermore false-negative IgM samples presented positive Reverse-IgM ELISA results even without adsorption with Staphylococcus aureus protein A . In a group of 104 sera samples from individuals with others pathologies, no interference was observed, even in the false-positive IgM samples due to the presence of IgM rheumatoid factor.


 

 

Texto completo disponível apenas em PDF.

Full text available only in PDF format.

 

 

REFERÊNCIAS BIBLIOGRÁFICAS

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Presente endereço:
Departamento de Ciências Fundamentais para a saúde
Universidade Federal de Uberlândia
MG, Brasil, CEP 38400

Recebido para publicação em 28-2-1985

 

 

Trabalho realizado no Laboratório de Imunologia do Instituto de Medicina Tropical de São Paulo.

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