Appearance and Localization of Plasmodium yoelii Circumsporozoite Protein during Sporogony in Anopheles stephensi

Abstract

The occurrence and distribution of circumsporozoite (CS) protein of Plasmodium yoelii 17X (lethal) was observed during sporogonic development in Anopheles stephensi mosquitoes. The CS protein was visualized by using a polyclonal antibody against synthetic peptides (QGPGAP) ₄ of the immunodominant repeats of the CS protein and immunogold labeling. The CS protein is synthesized in immature oocysts from day 5 after infective blood meal when sporozoite formation has not yet started. The CS protein appears on the plasmalemma of oocysts and associates with the surface of sporoblasts and budding sporozoites. Micronemes and the pellicle of mature sporozoites were immunolabeled.