Pregnancy Malaria: Pathogenesis and Immunity

妊娠期疟疾：发病机制和免疫

• 批准号: 8745592
• 负责人: Patrick Duffy
• 金额: $ 48.98万
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8745592
• 关键词: Adhesions; Affect; Affinity; Anemia; Animal Model; Animals; Anti-Inflammatory Agents; Anti-inflammatory; Antibodies; Antigens; Aotus primate; Area; Binding; CCL2 gene; Chondroitin Sulfate A; Commit; Complex; Goals; Human; Immunity; Inflammatory; Integral Membrane Protein; Interleukin-10; Link; Lipids; Low Birth Weight Infant; Malaria; Malaria Vaccines; Membrane; Membrane Proteins; Modeling; Molecular; Monkeys; Mus; Outcome; Parasites; Pathogenesis; Phenotype; Placenta; Plasmodium falciparum; Pre-Eclampsia; Pregnancy; Production; Proteins; Recrudescences; Resistance; Risk; Scientist; Serum; Severities; Spontaneous abortion; Surface; Surface Antigens; Surface Plasmon Resonance; Testing; Urea; Woman; cytokine; infant death; mouse model; neonatal death; nonhuman primate; novel; pregnant; receptor; research study; sodium carbonate; stillbirth; vaccine development

Pregnancy malaria (PM) affects estimated 50 million women worldwide and contributes to 200,000 infant deaths annually. Caused by sequestration of chondroitin sulfate A (CSA) binding Plasmodium falciparum parasites in placenta, PM increases risks of maternal anemia, stillbirth, spontaneous abortion, low birth weight, neonatal death, and preeclampsia. Previous ex vivo experiments have shown the mechanism of CSA binding in placenta can be inhibited by treating parasites with sera from multigravida women of malaria endemic area or animals immunized with antigens critical for parasite adhesion. LMIV is committed to develop pregnancy malaria vaccines that will protect women through production of anti-adhesion antibodies.During the past fiscal year, LMIV scientists have accomplished the following: 1. Established two novel animal models of pregnancy malaria. Using a panel of P. chabaudi isolates (heterologous strains AS, CB and ER have been under study), we have developed a mouse model of both malaria recrudescence and malaria reinfection during pregnancy in C57BL6 mice, and have found that malaria severity and poor outcomes are related to production of inflammatory cytokines such as TNFa and MCP1, and the anti-inflammatory cytokine IL10. Separately, we have developed the first ever non-human primate model of placental malaria, by showing the sequestration of P. falicparum parasites in the placenta of pregnant Aotus monkeys. 2. VAR2CSA is the primary determinant of P. falciparum adhesion to the placental receptor CSA. Recently, we have examined whether other parasite proteins contribute to the CSA-binding phenotype and now describe PfCSA-L as a novel surface antigen that associates with VAR2CSA on the surface knobs of Pf-IE. Over the past year, we have shown that PfCSA-L binds with high affinity to human placental CSPG by Surface Plasmon Resonance (SPR). Duo-Link analysis using DBL2X and PfCSA-L antibodies indicates that the proteins interact with each other; SPR analysis reveals that the DBL2X domain of VAR2CSA binds to PfCSA-L with subnanomolar affinity. Urea extraction of Pf-IE membranes suggests that both VAR2CSA and PfCSA-L are anchored by protein-protein (rather than protein-lipid) interactions on the IE surface , suggesting that they exist in complexes. Both VAR2CSA and PfCSA-L membrane proteins are resistant to alkaline sodium carbonate extraction, a hallmark of integral membrane proteins. These findings suggest that PfCSA-L interacts with VAR2CSA on surface knobs of Pf-IE, where it may contribute to the CSA-binding phenotype. As a highly conserved protein of small size (25 kDa), PfCSA-L appears to be a valuable target for placental malaria vaccine development.

妊娠期疟疾(PM)每年影响全球约5000万妇女，并导致20万婴儿死亡。由于软骨素硫酸盐A(CsA)结合的恶性疟原虫在胎盘中隔离，PM增加了母亲贫血、死产、自然流产、低出生体重、新生儿死亡和先兆子痫的风险。以往的体外实验表明，用疟疾流行区多胎妇女的血清或用寄生虫黏附关键抗原免疫的动物的血清处理寄生虫，可以抑制CsA在胎盘中结合的机制。 LMIV致力于开发孕期疟疾疫苗，通过生产抗粘连抗体来保护妇女。在过去的一年里，LMIV的科学家们完成了以下工作： 1.建立了两种新的孕期疟疾动物模型。使用一组查鲍迪原虫分离株(异源菌株AS、CB和ER一直在研究中)，我们在C57BL6小鼠中建立了疟疾复发和孕期疟疾再感染的小鼠模型，并发现疟疾的严重性和不良结局与炎性细胞因子如TNFa和MCP1以及抗炎细胞因子IL10的产生有关。另外，我们还建立了第一个非人类的胎盘疟疾灵长类动物模型，显示了恶性疟原虫在怀孕的奥图斯猴子的胎盘中的隔离。 2.VAR2CSA是恶性疟原虫与胎盘受体CsA黏附的主要决定因素。最近，我们研究了其他寄生虫蛋白是否与CsA结合表型有关，并将PfCSA-L描述为一种新的表面抗原，它与Pf-IE表面旋钮上的VAR2CSA结合。在过去的一年里，我们通过表面等离子体共振(SPR)证明PfCsA-L与人胎盘CSPG具有高亲和力。DBL2X和PfCSA-L抗体的Duo-Link分析表明这两种蛋白相互作用；SPR分析表明VAR2CSA的DBL2X结构域与PfCSA-L以亚纳摩尔亲和力结合。Pf-IE膜的尿素提取表明，VAR2CSA和PfCSA-L都是通过蛋白质-蛋白质(而不是蛋白质-脂)相互作用锚定在IE表面的，这表明它们存在于络合物中。VAR2CSA和PfCSA-L膜蛋白都不耐碱性碳酸钠提取，这是完整膜蛋白的标志。 这些发现表明，PfCSA-L与VAR2CSA在Pf-IE的表面旋钮上相互作用，可能与CsA结合表型有关。作为一种高度保守的小分子蛋白(25 KDa)，PfCSA-L似乎是胎盘型疟疾疫苗开发的一个有价值的靶点。