Molecular mechanism of malaria pathogenesis

摘要：鉴于在疟疾耐药性和病媒控制方面出现的新困难，以及持续缺乏有效疫苗，需要制定新的疟疾疫苗开发战略。我们采用一种新颖的方法合成并充分表征了含有恶性疟原虫保护性表位的多种抗原肽偶联物（MAPs），并在四种不同小鼠品系中评估了它们的免疫原性。本研究检测了含有两个肝期抗原-1 (LSA-1) t细胞表位的双表位MAP (T3-T1)，含有LSA-1和merozoite surface protein-1 (MSP-1) t细胞表位的双表位MAP，以及含有T3-T1和环孢子子蛋白（CSP）中心重复区有效b细胞表位的三表位MAP （T3-CS-T1）。四种菌株的小鼠均产生肽特异性抗体，但不同菌株小鼠的体液反应程度存在明显的遗传差异。抗map抗体在免疫荧光试验（IFA）中识别疟疾寄生虫的阶段特异性蛋白。此外，经三表位MAP T3-CS-T1免疫的杂交BALB/cJ x A/J CAF1小鼠血清在体外成功抑制了疟疾孢子子对肝癌细胞的侵袭。免疫小鼠的脾细胞在体外受免疫原刺激时也表现出基因限制性的细胞免疫反应。本研究表明，结合固相合成和偶联化学的表征良好的map是有效的免疫原，该方法可用于亚单位疫苗的开发。

Summary: Given the emerging difficulties with malaria drug resistance and vector control, as well as the persistent lack of an effective vaccine, new malaria vaccine development strategies are needed. We used a novel methodology to synthesize and fully characterize multiple antigen peptide conjugates (MAPs) containing protective epitopes from Plasmodium falciparum and evaluated their immunogenicity in four different strains of mice. A di-epitope MAP (T3-T1) containing two T-cell epitopes of liver stage antigen-1 (LSA-1), a di-epitope MAP containing T-cell epitopes from LSA-1 and from merozoite surface protein-1 (MSP-1), and a tri-epitope MAP (T3-CS-T1) containing T3-T1 and a potent B-cell epitope from the circumsporozoite protein (CSP) central repeat region were tested in this study. Mice of all four strains produced peptide specific antibodies, however the magnitude of the humoral response showed marked genetic variation between the different strains of mice. Anti-MAP antibodies recognized stage-specific proteins on the malaria parasites in an immunofluoresence assay (IFA). In addition, serum from hybrid BALB/cJ x A/J CAF1 mice that had been immunized with the tri-epitope MAP T3-CS-T1 successfully inhibited the malaria sporozoite invasion of hepatoma cells in vitro. Spleen cells from immunized mice also showed a genetically restricted cellular immune response when stimulated with the immunogen in vitro. This study indicates that well-characterized MAPs combining solid phase synthesis and conjugation chemistries are potent immunogens and that this approach can be utilized for the development of subunit vaccines.