The roles of the glycosylphosphatidylinositol anchor on the production and immunogenicity of recombinant ookinete surface antigen Pbs21 of Plasmodium berghei when prepared in a baculovirus expression system.

摘要: Malarial ookinetes express an immunodominant surface protein (P28) that is a priority candidate for the development of transmission-blocking vaccines. The full length P28 gene from Plasmodium berghei [Pbs21(1–213)] and deletion construct [Pbs21(1–188)] encoding lacks 25 C-terminal amino acids, including glycosylphosphatidylinositol (GPI) anchor signal, were expressed in insect cells using baculovirus vectors. Pbs21(1–213) strongly hydrophobic, found cytoplasm on Spodoptera Sf21 cells, culture medium. Pbs21(1–188) was largely aqueous phase medium but not detected cell surface. presence acids therefore critical to attachment recombinant Pbs21 parasite plasma membrane. Mice immunized subcutaneously or intramuscularly with affinity purified Pbs21(1–213), native proteins. Following two immunizations, induces higher titres when administered by either route, than bearing GPI anchor, which turn markedly more immunogenic polypeptide lacking anchor. When specific anti antibody exceeded 1 mg/ml all three antigens capable inducing transmission blockade ≥ 90%, below did correlate concentration.