A SIMPLIFIED METHOD FOR THE FRACTIONATION OF GNATHOSTOMA-SPECIFIC ANTIGENS FOR SERODIAGNOSIS OF HUMAN GNATHOSTOMOSIS

Specific immunoreactive components present in crude somatic extract an d in excretory-secretory (ES) products of Gnathostoma spinigerum advan ced third-stage larvae (L3) were identified by Western blotting and th eir diagnostic potential evaluated by indirect ELISA. Although both cr ude antigen preparations were highly complex, the ES antigen gave a mo re satisfactory diagnostic result. Most G. spinigerum specific compone nts present in the somatic and ES preparations had molecular weights b elow 29 kD and were not glycosylated, judging from the concanavalin A staining pattern. Specific diagnostic antigens were prepared by subjec ting the crude preparations to SDS-PAGE. Low molecular weight componen ts were identified and electroeluted from the gel. Excess SDS was remo ved by the use of an ion retardation resin. The antigens obtained by t his relatively simple procedure were found to be highly specific for G . spinigerum. Sensitivity, specificity, and positive and negative pred ictive values for the assay using the fractionated somatic antigen wer e 100%.