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Immunoaffinity isolation of Schistosoma mansoni species-specific molecules using monoclonal antibodies.

1,2Ahmed M Osman, 2Hannaa Hassan, 1,2Maged M Al-Sherbiny, 3Nabil Galal and 1Abdel Hakim Saad.

1Zoology Department, Faculty of Science, Cairo University, 2Egyptian Reference Diagnostic Center (E-RDC), VACSERA and 3Tropical Medicine Research Institute, Kasr El-Eini, Cairo, Egypt.

 Traditional diagnosis of schistosomiasis by stool and urine examination techniques is both insensitive and labor intensive. Many efforts are directed towards the development of alternate sensitive and specific assays for diagnosis of schistosomiasis. With the development of hybridoma technology, monoclonal antibodies (MoAb) with high specificity to diagnostic antigens could be produced. In the present study, a species-specific fraction namely, Gp30 prepared from S. mansoni microsomal antigen (MAMA) was purified by a simple, easy and cheap apparatus (491-prep cell) (Bio-Rad). Balb/c mice were immunized with the isolated glycoprotein (Gp) to produce a panel of MoAbs, which can be used to immunoaffinity purify target antigen. Among the produced panel, 6B3-1B432 MoAb of IgG2a isotope was able to detect 10-20 ng of Gp30 antigen in ELISA (O.D650 = 1.985) and dot blot. In immunoblotting, 6B3-1B432 recognized only one band in the MAMA antigens, namely Gp30. This MoAb was purified with protein G Suprose using FPLC and PD-10 column and consequently used to immunoaffinity purify target antigen. The specificity and sensitivity of the immunoaffinity purified Gp30 (IP Gp30) was determined before using it in the dipstick assay. Our results indicated the absolute specificity of IP Gp30 and sensitivity results, 98%, was comparable to that obtained by the electroeluted GP30. The simplicity of the purification and the efficacy of the dipstick assay may render this diagnostic method for widespread use in the field of schistosomiasis.