Comparison of surface iodination methods by electron microscopic autoradiography applied in vitro to different life-stages ofDipetalonema vitae(Filarioidea)

Abstract

Different stages of D. viteae (males, females, microfilariae, and 3rd-stage larvae) were iodinated in vitro under physiological conditions by chloroglycoluril, lactoperoxidase or chloramine T. The concentrations of the catalyssts were correlated with the viability of the worms. Localization of the label with the different iodination methods were visualized by EM autoradiography. Chloroglycoluril-mediated iodination is predominately localized on the filarial cuticle. Lactoperoxidase-catalyzed iodination is less specific and chloramine T catalyzes iodination in a gradient decreasing from the cuticle to inner structures. It is necessary to visualize the labeling by EM autoradiography prior to biochemical and immunological experiments to avoid the extraction of structures iodinated by leakage of the catalyst into the sub-cuticular regions.