A modified Gedelisa [gel electrophoresis derived enzyme linked immunosorbent assay, ELISA] test is described. The gel gradient, after electrophoretic migration, is cut longitudinally. Half is stained with Coomassie blue and the 2nd half is cut in slices of 1 mm thick. Each slice is placed in a well of a microtitration polystyrene plate, filled up with carbonate buffer pH 9.6 and then scratched. Proteins diffuse out of the gel and coat on the polystyrene. The antigenicity of the coated proteins is revealed by ELISA test. This technique was applied to the study of T. gondii exo-antigens obtained from a medium of in vitro culture on Vero cells. This antigen contains 4 fractions, 3 of which are stained with Coomassie blue; their MW are 160,000, 83,000 and > 1 million daltons.