ABSTRACT
Schistosoma mansoni surface membrane components play a relevant role in the host-parasite interaction, and some are released in vivo as circulating antigens. n-Butanol extraction favors the release of membrane antigens like alkaline phosphatase, which has been shown to be specifically recognized by antibodies from S. mansoni-infected humans and animals. In the present study, components in the n-butanol extract (BE) of the adult S. mansoni worm membrane fraction were separated by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (1D SDS-PAGE [15%]) and further analyzed by immunoblotting (immunoglobulin G) using defined sera. S. mansoni-infected patient sera, but not sera of uninfected patients or sera obtained from patients infected with other parasite species, specifically and variably recognized up to 20 polypeptides in the molecular mass range of approximately 8 to >80 kDa. There were some differences in the number, intensity, and frequency of recognition of the BE antigens among sera from Venezuelan sites of endemicity with a different status of schistosomiasis transmission. Antigens in the 28- to 24-kDa molecular mass range appeared as immunodominants and were recognized by S. mansoni-positive sera from all the sites, with recognition frequencies varying between 57.5 and 97.5%. Immunoblotting with BE membrane antigens resulted in a highly sensitive (98.1%), specific (96.1.0%), and confirmatory test for the immunodiagnosis of schistosomiasis in low-transmission areas.
Subject(s)
Antigens, Helminth/immunology , Schistosoma mansoni/isolation & purification , Schistosomiasis mansoni/diagnosis , Adolescent , Adult , Animals , Antigens, Surface/immunology , Cell Membrane/immunology , Humans , Immunoblotting , Immunoglobulin G/immunology , Prevalence , Schistosoma mansoni/immunology , Schistosomiasis mansoni/immunology , Schistosomiasis mansoni/transmission , Venezuela/epidemiologyABSTRACT
El inmunoensayo para la Fosfatasa Alcalina (IEFA) detecta la presencia de anticuerpos antifosfatasa alcalina de la membrana de los vermes adultos de schistosoma mansoni. Su valor disgnóstico fue probado con 1514 sueros de personas de tres comunidades diferentes del área endémica del interior de Venezuela y 322 sueros de personas del área capitalina de Caracas, encontrandose una sensibilidad de 91,1 por ciento-96,8 por ciento con respecto a la Elisa (con antígenos de huevo). El IEFA fue 100 por cierto específico con sueros de sujetos residentes en localidades no endémicas. Esta metodología mostró menor 84 por cierto de concordancia (Prueba "kappa" de cohen) con "western blot" de antígenos de membrana del adulto y concordancia positiva con la PPCO (40, 6-77,1 por ciento) y la ELISA (51,4-69,1 por ciento) en las poblaciones endémicas estudiadas. Los resultados indican que IEFA es aplicable a la pesquisa epidemiológica de la esquistosomiasis mansoni en zonas endémicas y que la prueba es muy sensible para la detección de casos con baja carga parasitaria (au)
