Development of novel malaria pre-erythrocytic vaccine antigens targeting Plasmodium sporozoite liver infection

以前，我们的研究小组利用噬菌体肽展示文库鉴定了疟原虫寄生虫配体， 相应的宿主细胞受体，对于哺乳动物肝脏中的子孢子-库普弗细胞相互作用是重要的。 使用类似的方法，我们鉴定了HP 1肽，一种子孢子 用于感染肝细胞。用HP 1肽免疫保护约50%的小鼠免受伯氏疟原虫感染 挑战.使用抗HP 1抗体，我们鉴定了疟原虫磷脂扰乱酶（PLS）作为 肝细胞的子孢子配体和潜在的疫苗抗原。我们建议1）鉴定PLS蛋白 在肝细胞识别中起作用的表位，用作疫苗抗原;和2）开发三- 功能性疫苗抗原，其包含i）靶向肝的子孢子环子孢子蛋白（CSP）表位 窦状隙结合，ii）子孢子GAPDH相关表位，靶向子孢子通过 枯否细胞穿越，和iii）子孢子PLS表位，靶向肝细胞感染。我们期望这 方法将导致最先进的RTS，S/AS 01的中度保护效果的增强 疟疾疫苗

Previously, using a phage peptide display library, our group has identified Plasmodium parasite ligands and corresponding host cell receptors important for sporozoite-Kupffer cell interaction in the mammalian liver. Using a similar approach, we identified the HP1 peptide, a structural mimic of a ligand that the sporozoite uses to infect hepatocytes. Immunization with the HP1 peptide protects ~ 50 % mice from P. berghei challenge. Using an anti-HP1 antibody, we identified Plasmodium Phospholipid Scramblase (PLS) as the sporozoite ligand of hepatocytes and a potential vaccine antigen. We propose 1) to identify PLS protein epitopes that function in hepatocyte recognition, for use as a vaccine antigen; and 2) to develop a tri- functional vaccine antigen containing i) a sporozoite circumsporozoite protein (CSP) epitope, targeting liver sinusoid binding, ii) a sporozoite GAPDH-related epitope, targeting sporozoite exit from the circulation via Kupffer cell traversal, and iii) sporozoite PLS epitope, targeting hepatocyte infection. We expect that this approach will lead to enhancement of the moderate protective efficacy of the most advanced RTS,S/AS01 malaria vaccine.