Abstract

COLMENARES, Cecilia; MENDEZ, Liber; DIAZ-BELLO, Zoraida  and  ALARCON DE NOYA, Belkisyolé. Fasciola hepatica excretion-secretion antigen: ultrafiltration and application in immunodiagnosis. Acta bioquím. clín. latinoam. [online]. 2007, vol.41, n.2, pp.259-266. ISSN 0325-2957.

Low sensitivity in the coprologic diagnosis of human fasciolosis has motivated the development of immunodiagnosis. The excretion-secretion antigen from Fasciola hepatica adult worms (ESAFh) with ELISA is suitable for screening, although it overestimates its prevalence. However, when tested by Western blot (WB) it does not show any optimal recognition of its components. In order to obtain a better preparation, the antigen was ultrafiltered by YM 10, 30 and 50 kDa membranes. Retentates (R) were used by ELISA and WB. A higher discrimination between positives and negatives by ELISA and a better resolution in the antigen recognition in WB was achieved with the R50 fraction. Molecules of 9, 14, 65 kDa, and region about 27 kDa were detected with high sensitivity (90 to 100% of positive sera) and specificity (none of the negative sera). Among the 29 sera with other parasitic diseases, only one with Paragonimus sp. reacted to the 65 kDa molecule. ELISA-ESAFh with all filtrated fractions was useful, facilitating the infection screening even though the best results were obtained with R50. The verification of positive cases is efficiently achieved using the R50 of the ESAFh fraction by WB.

Keywords : fasciolosis; antigen; ultrafiltration; immunodiagnosis; ELISA; Western blot.

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