Diferenciação entre os estágios agudo e crônico na infecção toxoplásmica pela técnica de aglutinação direta modificada
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Data
2006-07-10
Autores
Silva, Rodrigo Costa da [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O Toxoplasma gondii é um protozoário parasita de grande importância no contexto de produção animal e saúde pública, envolvendo alterações fetais e abortos na espécie humana e em animais, sendo ainda importante patógeno oportunista em pacientes imunocomprometidos. A técnica de aglutinação direta modificada (MAT) destaca-se por independer da origem dos anticorpos e permitir diferenciar os estágios da infecção toxoplásmica. Assim, padronizou-se a técnica de sedimentação espontânea, verificando-se que com 60 minutos, a parte líquida da suspensão apresentava predominantemente taquizoítos e raras células pequenas. O antígeno inativado pelo metanol (AM) permitiu a exposição de antígenos de fase aguda somente, enquanto que a formalina (AF) expõe tanto os de fase aguda como crônica. Testou-se o antígeno para três grupos experimentais: G1, ratas infectadas com 104 bradizoítos da cepa BTU10, genótipo I, via oral; G2, ratas infectadas com 104 bradizoítos da cepa BTU10, via oral, e imunodeprimidas com corticóide; G3, grupo controle. A comparação das MATs permitiu a diferenciação dos anticorpos IgG de fase aguda, dos de fase crônica. Gradativamente foi obtida a maturação dos anticorpos, sendo observada pela avidez das mesmas no teste de ELISA. Os anticorpos do grupo experimental se comportaram semelhantemente para as provas sorológicas, até a 13ª semana. A reagudização no G2 foi detectada na bioprova da musculatura antes que no cérebro. Com isso, verificou-se que a MAT-AM e a MAT-AF permitem a diferenciação dos estágios agudo e crônico, e ainda a caracterização da reagudização da infecção em pacientes imunocomprometidos.
Toxoplasma gondii is a parasite protozoan with great importance to animal production and public health, involving foetal alterations and abortions in human and animal species, being an important opportunistic pathogen in immunocompromised patients. Modified agglutination test (MAT) has great importance to independ of the origin of antibody, and to allow differentiating the periods of the Toxoplasma infection. Thus, the protocol of spontaneous sedimentation we standardized, verifying that with 60 minutes, the liquid part of the suspension showed predominantly the presence of tachyzoites and rare small cells. The antigen inactivated with methanol (AM) allowed the exposition of antigens of acute phase only, while formalin (AF) as much the acute as chronic phase. Antigen was tested to three experimental groups: G1, rats infected with 104 bradyzoites of BTU10 strain, genotype I, orally; G2, rats infected with 104 bradyzoites of BTU10 strain, orally, and immunodepressed with corticoid; G3, control group. The comparation of MATs allows the differentiation of IgG from acute phase of the ones from chronic phase. A gradual maturation of immunoglobulins was gotten, being observed through the avidity of the same ones, and surveyed for ELISA. The antibodies of the experimental groups showed similar profile for all serological tests, until the 13th week. Reacutization of the infection in G2 was detected earlier in bioassay of musculature than brain. Thus, we verified that MAT-AM and MAT-AF allow the differentiation of the acute and chronic stages, and still the characterization of the reacutization of the infection in immunocompromised patients.
Toxoplasma gondii is a parasite protozoan with great importance to animal production and public health, involving foetal alterations and abortions in human and animal species, being an important opportunistic pathogen in immunocompromised patients. Modified agglutination test (MAT) has great importance to independ of the origin of antibody, and to allow differentiating the periods of the Toxoplasma infection. Thus, the protocol of spontaneous sedimentation we standardized, verifying that with 60 minutes, the liquid part of the suspension showed predominantly the presence of tachyzoites and rare small cells. The antigen inactivated with methanol (AM) allowed the exposition of antigens of acute phase only, while formalin (AF) as much the acute as chronic phase. Antigen was tested to three experimental groups: G1, rats infected with 104 bradyzoites of BTU10 strain, genotype I, orally; G2, rats infected with 104 bradyzoites of BTU10 strain, orally, and immunodepressed with corticoid; G3, control group. The comparation of MATs allows the differentiation of IgG from acute phase of the ones from chronic phase. A gradual maturation of immunoglobulins was gotten, being observed through the avidity of the same ones, and surveyed for ELISA. The antibodies of the experimental groups showed similar profile for all serological tests, until the 13th week. Reacutization of the infection in G2 was detected earlier in bioassay of musculature than brain. Thus, we verified that MAT-AM and MAT-AF allow the differentiation of the acute and chronic stages, and still the characterization of the reacutization of the infection in immunocompromised patients.
Descrição
Palavras-chave
Toxoplasmose - Estudos experimentais, Toxoplasma gondii, Infecção experimental, Sorologia, Experimental infection, Serology, Rattus norvegicus
Como citar
SILVA, Rodrigo Costa da. Diferenciação entre os estágios agudo e crônico na infecção toxoplásmica pela técnica de aglutinação direta modificada. 2006. 135 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Medicina Veterinária e Zootecnia, 2006.