Genetic and functional studies of var2csa in placental malaria

var2csa 在胎盘疟疾中的遗传和功能研究

基本信息

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
项目类别：
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

项目摘要

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（由申请人提供）：每年胎盘和数百万孕妇和新生儿的恶性疟疾寄生虫遗体。隔离由恶性疟原虫Var2CSA蛋白介导的插入的红细胞表面上，该蛋白与胎盘硫酸盐硫酸盐A（CSA）结合，产生胎盘炎症，并导致低出生体重（LBW）婴儿。对VAR2CSA的适应性免疫可保护孕妇和新生儿免受疟疾的发病率。 VAR2CSA较大且多样化，未经完整描述的抗原和免疫原性结构域，但是VAR2CSA的一个2.4 Kb区域编码ID1-DBL2X-ID2，该ID1-DBL2X-ID2在体外表达时结合具有高亲和力的CSA。这种重组蛋白会引起有效的结合抑制抗体，因此作为疫苗候选者具有巨大的希望。但是，由于VAR2CSA高度多样，因此可能需要进行多价疫苗。在这里，我们建议询问VAR2CSA ID1-DBL2X-ID2多样性，并确定马拉维孕妇的潜在致病性变异，然后测量表达重组者的CSA结合和免疫原性。将从1600人的试验中选择200名孕妇和分娩寄生虫的孕妇，该试验将间歇性筛查和治疗（IST）与间歇性预防疗法（IPT）进行比较。它们将分为4组：Primigravidae，有或没有低出生体重（LBW）后代和有或没有LBW后代的Multigravidae。从每个妇女那里，我们将获得3个寄生虫样本：第二个三个月的外周血，分娩以及胎盘血的血液。对于第一个目标，将汇总每个组的每种样本类型（12个池），并在ID1-DBL2X-ID2区域进行深入序列。我们将确定与原始性和LBW相关的变体。在第二个目标中，我们将使用QPCR和逆转录酶QPCR比较怀孕期间每个妇女中50种最常见变体的人口大小。我们假设，在第二个三个月中，最常见的变异性变异比分娩时更为普遍。在第三个目标中，我们将合成最适合这些标准并测量其体外CSA结合和免疫原性的变体的重组。该提案代表了UNC小组之间的新合作，具有流行病学和深度测序方面的专业知识，以及VAR2CSA生物学和疫苗开发领域的领导者哥本哈根大学。该提案将有助于阐明妊娠中疟疾的发病机理，并直接告知疫苗与妊娠相关疟疾的持续开发。