ABSTRACT
To know if alkaline phosphatase (AP) from schistosomes other than Schistosoma mansoni can be used as diagnostic marker for schistosomiasis in alkaline phosphatase immunocapture assay (APIA), we comparatively tested n-butanol extracts of adult worm membranes from a Venezuelan (JL) strain of S. mansoni (Ven/AWBE/Sm); a Cameroonian (EDEN) strain of Schistosoma intercalatum (Cam/AWBE/Si) and a Yemeni strain of Schistosoma haematobium (Yem/AWBE/Sh). APIA was evaluated with sera of patients from Venezuela, Senegal, and Gabon infected with S. mansoni, from Gabon infected with S. intercalatum or S. haematobium, from Chine infected with Schistosoma japonicum and from Cambodian patients infected with Schistosoma mekongi. Results indicate that 92.5% (37/40) of Venezuela sera, 75% (15/20) of Senegal sera, 39.5% (17/43) of S. haematobium sera, and 19.2% (5/26) S. intercalatum sera were APIA-positive with the Ven/AWBE/Sm preparation. APIA with the Cam/AWBE/Si preparation showed that 53.8% of S. intercalatum-positive sera had anti-AP antibodies, and 51.2% S. haematobium-positive sera cross-immunocapturing the S. intercalatum AP. APIA performed with Yem/AWBE/Sh showed that 55.8% S. haematobium sera were positive. Only two out of nine S. japonicum sera were APIA-positive with the Ven/AWBE/Sm and Cam/AWBE/Si, and no reaction was observed with Cambodian S. mekongi-positive sera. AP activity was shown to be present in all the schistosome species/strains studied. The use of APIA as a tool to explore the APs antigenicity and the presence of Schistosoma sp. infections through the detection of anti-Schistosoma sp. AP antibodies in a host, allowed us to demonstrate the antigenicity of APs of S. mansoni, S. intercalatum, and S. haematobium.
Subject(s)
Alkaline Phosphatase/immunology , Schistosoma/enzymology , Schistosomiasis/immunology , Animals , Antibodies, Helminth/blood , Antigens, Helminth/immunology , Cambodia , Female , Gabon , Humans , Male , Schistosoma/classification , Schistosoma/immunology , Schistosoma haematobium/enzymology , Schistosoma haematobium/immunology , Schistosoma japonicum/enzymology , Schistosoma japonicum/immunology , Schistosoma mansoni/enzymology , Schistosoma mansoni/immunology , Schistosomiasis/diagnosis , Senegal , VenezuelaABSTRACT
The species specificity of the solid phase alkaline phosphatase immunocapture assay (APIA) for the immunological detection of human immunoglobulin G antibodies to the alkaline phosphatase of adult Schistosoma mansoni was evaluated. Sera from schistosomiasis patients from South America, West Africa, south-east Asia and uninfected control subjects were compared. Only the sera of patients infected with S. mansoni gave positive results. There was no apparent difference between 2 populations infected with S. mansoni, one from South America and the other from West Africa. The results with sera from various regions of West Africa were also indistinguishable. Although the APIA was not able to discriminate the geographical origin of the S. mansoni-infected subjects, the method appeared to be specific for S. mansoni and suitable for use in the immunodiagnosis of schistosomiasis mansoni, particularly in endemic areas where mixed infections of Schistosoma spp. occur.