Genetic and functional studies of var2csa in placental malaria

var2csa 在胎盘疟疾中的遗传和功能研究

• 批准号: 8785243
• 负责人: Steven Richard Meshnick
• 金额: $ 31.84万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-15 至 2015-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8785243
• 关键词: Adverse effects; Affinity; Alleles; Antibodies; Area; Avidity; Baculoviruses; Binding; Biochemistry; Biological; Biological Assay; Biology; Biosensor; Birth; Birth Weight; Blood; Cells; Chondroitin Sulfate A; Clinical Data; Cloning; Code; Codon Nucleotides; Collaborations; DNA; Development; Dideoxy Chain Termination DNA Sequencing; Engineering; Enrollment; Epidemiology; Erythrocytes; Falciparum Malaria; Foundations; Funding; Genes; Genetic; Goals; Gravidity; Health; ID2 gene; In Vitro; Individual; Inflammation; Insecta; Ligand Binding; Link; Longitudinal Studies; Low Birth Weight Infant; Malaria; Malaria Vaccines; Malawi; Measures; Mediating; Membrane; Morbidity - disease rate; Newborn Infant; Outcome; Parasitemia; Parasites; Pathogenesis; Pathogenicity; Patients; Persons; Placenta; Plasmodium falciparum; Polyvalent Vaccine; Population Dynamics; Population Sizes; Pregnancy; Pregnant Women; Prevention; Preventive; Primigravidities; Proteins; RNA; RNA-Directed DNA Polymerase; Reaction; Recombinant Proteins; Recombinants; Research; Research Personnel; Sampling; Second Pregnancy Trimester; Serum; Surface; System; Technology; Universities; Ursidae Family; Vaccines; Variant; Woman; Work; acquired immunity; adaptive immunity; base; cohort; deep sequencing; feeding; immunogenic; immunogenicity; immunoreactivity; innovation; next generation; offspring; peripheral blood; prevent; screening; trial comparing; vaccine candidate; vaccine development

DESCRIPTION (provided by applicant): Falciparum malaria parasites sequester in placentae and imperil millions of pregnant women and newborns each year. Sequestration is mediated by P. falciparum VAR2CSA proteins inserted on the erythrocyte surface which bind to placental chondroitin sulfate A (CSA), produce placental inflammation, and result in low birth weight (LBW) babies. Adaptive immunity to VAR2CSA protects pregnant women and newborns from malaria morbidity. VAR2CSA is large and diverse with incompletely described antigenic and immunogenic domains, but one 2.4 kb region of var2csa, encodes ID1-DBL2X-ID2, which binds CSA with high affinity when expressed in vitro. This recombinant protein elicits potent binding inhibitory antibodies and thus has great promise as a vaccine candidate. However, because VAR2CSA is highly diverse, a polyvalent vaccine might be necessary. Here we propose to interrogate var2csa ID1-DBL2X-ID2 diversity and identify potentially pathogenic variants in Malawian pregnant women, and then measure the CSA binding and immunogenicity of expressed recombinants. 200 pregnant women with both 2nd trimester and delivery parasitemias will be selected from a 1600-person trial comparing Intermittent Screening and Treatment (IST) with Intermittent Preventive Therapy (IPT). They will be divided into 4 groups: primigravidae with and without low-birth weight (LBW) offspring and multigravidae with or without LBW offspring. From each woman, we will obtain 3 parasite samples: peripheral blood from the 2nd trimester and from delivery, and from placental blood. For the first aim, each sample type from each group will be pooled (12 pools) and deep-sequenced across the ID1-DBL2X-ID2 region. We will identify variants associated with primigravidity and LBW. In the second aim, we will use qPCR and reverse-transcriptase qPCR to compare population sizes of the 50 most common variants within each woman over the course of pregnancy. We hypothesize that the most pathogenic variants will be more common in the 2nd trimester than at delivery. In the third aim, we will synthesize and express recombinants of the variants that best fit these criteria and measure both their in vitro CSA-binding and immunogenicity. This proposal represents a new collaboration between the UNC group, with expertise in epidemiology and deep sequencing, and the University of Copenhagen group, a leader in var2csa biology and vaccine development. This proposal will help elucidate the pathogenesis of malaria in pregnancy and directly inform the on-going development of a vaccine against pregnancy-associated malaria.

描述(申请人提供)：恶性疟疾寄生虫隔离在胎盘中，每年危及数百万孕妇和新生儿。恶性疟原虫VAR2CSA蛋白与胎盘硫酸软骨素A(CsA)结合，产生胎盘炎症，导致低出生体重(LBW)婴儿。对VAR2CSA的适应性免疫保护孕妇和新生儿免受疟疾发病率的影响。VAR2CSA大而多样，抗原区和免疫原区尚未完全描述，但VAR2csa的一个2.4kb区域编码ID1-DBL2X-ID2，它在体外表达时与CsA具有高亲和力。这种重组蛋白能产生有效的结合抑制抗体，因此很有希望成为疫苗候选。然而，由于VAR2CSA高度多样化，可能有必要接种多价疫苗。在这里，我们建议询问var2csa ID1-DBL2X-ID2的多样性，并在马拉维孕妇中鉴定潜在的致病变异，然后测量表达的重组体的CsA结合和免疫原性。200名患有中期妊娠和分娩寄生虫病的孕妇将从一项1600人的试验中挑选出来，该试验比较了间歇筛查和治疗(IST)和间歇预防治疗(IPT)。它们将被分成4组：有或没有低出生体重(LBW)后代的原始妊娠病毒科和有或没有LBW后代的多胎妊娠科。从每名妇女身上，我们将获得3个寄生虫样本：中期妊娠和分娩时的外周血液，以及胎盘血。对于第一个目标，来自每一组的每种样本类型将被汇集(12个池)，并在ID1-DBL2X-ID2区域进行深度测序。我们将确定与原始妊娠和LBW相关的变异。在第二个目标中，我们将使用定量聚合酶链式反应和逆转录酶定量聚合酶链式反应来比较怀孕期间每个女性体内最常见的50种变异的群体大小。我们推测，最常见的致病变异在妊娠中期比分娩时更常见。在第三个目标中，我们将合成和表达最符合这些标准的突变体的重组体，并测量它们在体外与CsA的结合和免疫原性。这项提议代表了在流行病学和深度测序方面拥有专业知识的北卡罗来纳大学小组和在var2csa生物学和疫苗开发方面处于领先地位的哥本哈根大学小组之间的新合作。这一建议将有助于阐明妊娠疟疾的发病机制，并直接为正在开发的与妊娠相关的疟疾疫苗提供信息。