Radioiodination of parasite antigens with 1,3,4,6-tetrachloro-3 alpha, 6 alpha-diphenylglycoluril (IODOGEN): studies with zygotes of Plasmodium gallinaceum.

The iodinating reagent 1,3,4,6-tetrachloro-3 alpha, 6 alpha-diphenylglycoluril (IODOGEN) was used to label antigens on zygotes of Plasmodium gallinaceum with parallel studies using lactoperoxidase-catalyzed radioiodination for comparison. Proteins labeled by the IODOGEN method are most probably on the surface of the zygote, as the pattern of labeled proteins analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was very similar to the pattern of lactoperoxidase-labeled proteins. Furthermore, the labeled proteins represented only a subset of the total Coomassie Blue-stained proteins. The radioiodinated zygote proteins were immunoreactive after IODOGEN or lactoperoxidase labeling. The IODOGEN method is technically much more simple than the lactoperoxidase method and does not require the addition of extraneous proteins or H2O2. The advantages of IODOGEN labeling, together with the essential equivalence of results obtained by these two methods, make the IODOGEN method attractive for labeling parasite antigens in general.