RESUMO
Schistosoma circulating antigens were used for the detection of active infection. Anti-S. mansoni IgG2a monoclonal antibody (MAb) designated C5C4 was generated. The target epitope of this MAb was detected in adult worms, eggs, and cercariae antigenic extracts of S. mansoni and S. haematobium, had a molecular size of 63 kD, and was not detected in Fasciola hepatica and Ascaris. In addition, a 50-kD degradation product was identified only in the urine of infected individuals. Analysis by high-performance liquid chromatography of the purified antigen demonstrated only one peak. The 63-kD antigen was characterized as a protein containing 40.4% hydrophobic, 7.5% acidic, and 8.8% basic amino acids. The C5C4 MAb was used in a Fast Dot-ELISA for rapid and simple diagnosis of human schistosomiasis. The 63-kD circulating antigen was detected in 92% of urine samples from 330 S. mansoni-infected individuals, with 16% false-positive results among 130 noninfected individuals.
Assuntos
Antígenos de Helmintos/análise , Enteropatias Parasitárias/diagnóstico , Schistosoma haematobium/isolamento & purificação , Schistosoma mansoni/isolamento & purificação , Esquistossomose Urinária/diagnóstico , Esquistossomose mansoni/diagnóstico , Adolescente , Adulto , Aminoácidos/análise , Animais , Anticorpos Monoclonais/imunologia , Antígenos de Helmintos/química , Antígenos de Helmintos/urina , Ascaris lumbricoides/imunologia , Western Blotting , Criança , Cromatografia Líquida de Alta Pressão , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Reações Falso-Positivas , Fasciola hepatica/imunologia , Fezes/parasitologia , Feminino , Humanos , Enteropatias Parasitárias/imunologia , Masculino , Camundongos , Pessoa de Meia-Idade , Peso Molecular , Contagem de Ovos de Parasitas , Reto/parasitologia , Schistosoma haematobium/imunologia , Schistosoma mansoni/imunologia , Esquistossomose Urinária/imunologia , Esquistossomose mansoni/imunologiaRESUMO
An IgG2a anti-Schistosoma mansoni mouse monoclonal antibody was shown to passively protect Swiss mice. The 74 kDa target antigen was isolated from antigenic extracts of S. mansoni adult worms. Swiss and C57 BL/6J mice were immunized with 30, 50, 100 and 200 microg antigen/mouse doses with and without Freund's adjuvant. Sera of immunized mice showed high reactivity against 74 kDa antigen. The highest protection level (76.6% in Swiss mice and 50.1% in C57 BL/6J mice) was obtained using the 50 microg antigen dose with and without Freund's adjuvant. A marked reduction in granuloma number and intensity of collagen and reticular granuloma fibers was observed. The 74 kDa antigen has the ability to protect mice of different strains and to modulate the host immune system.