Plasmodium vivax 48/45 gametocyte protein: functional characterization and vaccine potential assessment in preclinical studies

间日疟原虫 48/45 配子体蛋白：临床前研究中的功能表征和疫苗潜力评估

• 批准号: 9305832
• 负责人: Myriam Arevalo-Herrera
• 金额: $ 42.47万
• 依托单位: MALARIA VACCINE DEVELOPMENT CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2020-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9305832
• 关键词: Address; Adjuvant; Affinity; Affinity Chromatography; Age; Alhydrogel; Animals; Anopheles Genus; Antibodies; Antibody Response; Antibody Specificity; Antibody titer measurement; Antigens; Area; B-Lymphocytes; Bioinformatics; Biological Assay; Biophysics; Blocking Antibodies; Blood; Brazil; Burkina Faso; Cells; Circular Dichroism; Colombia; Colombian; Culicidae; Data; Development; Disease; Enzyme-Linked Immunosorbent Assay; Epitopes; Escherichia coli; Fertilization; Flow Cytometry; Goals; Human; Immune; Immune response; Immunity; Immunization; Immunize; Immunoglobulin G; Individual; Infection; Interruption; Lead; Length; Location; Malaria; Maps; Mass Spectrum Analysis; Measures; Methods; Modeling; Molecular Models; Monkeys; Montanide ISA-51; Mus; NMR Spectroscopy; Parasites; Participant; Patients; Peptides; Peripheral Blood Mononuclear Cell; Pilot Projects; Plasmodium; Plasmodium falciparum; Plasmodium vivax; Plasmodium vivax vaccine; Primates; Production; Protein Fragment; Proteins; Recombinant Proteins; Recombinants; Rodent; ST13 gene; T cell response; T-Cell Proliferation; T-Lymphocyte Epitopes; Techniques; Tertiary Protein Structure; Testing; Vaccination; Vaccine Design; Vaccines; age related; base; biophysical analysis; clinical development; cost effective; cross reactivity; cytokine; design; domain mapping; epidemiologic data; experience; immunogenic; immunogenicity; malaria infection; malaria transmission; molecular modeling; nonhuman primate; pre-clinical; preclinical study; prevent; protein folding; public health relevance; structural biology; synthetic peptide; three dimensional structure; transmission process; transmission-blocking vaccine; vaccine candidate; vaccine development; vaccine discovery; vaccine trial; vector mosquito; volunteer; zygote

 DESCRIPTION (provided by applicant): Individuals continuously exposed to malaria infections in endemic areas develop immune responses that have been shown to reduce or block parasite transmission from patients to the mosquito vector in what is called transmission-blocking (TB) immunity. In this context, antibodies (Abs) targeting specific Plasmodium antigens expressed on gametocyte, zygote, and ookinete stages can induce this blockage, providing the bases for the development of TB vaccines. One of these antigens, P48/45 is a conserved protein expressed in all Plasmodium species, required for parasite fertilization, and currently being developed as a vaccine candidate for P. falciparum. The P. vivax orthologue, cloned and expressed in E. coli, as a ~60kDa recombinant product has been shown to be highly antigenic and immunogenic. Individuals exposed to P. vivax produce Abs to Pvs48/45 which increases in an age dependent manner, and those individuals with higher a-Pvs48/45 Ab titers also display high ex vivo TB activity. Pilot studies have shown that the rPvs48/45 protein is highly immunogenic both in mice and monkeys and Abs elicited have the capacity to ex vivo block parasite transmission to mosquitoes. Together, all these data make Pvs48/45 a very promising TB vaccine candidate. The goal of this proposal is to determine the vaccine potential of rPvs48/45 for human use. We will further characterize the antigenicity of rPvs48/45 using sera and cells of individuals from endemic areas, and rPvs48/45 domains and synthetic peptides to map the relevant immune and functional epitopes. Additionally, we will confirm and further characterize the immunogenicity of full length Pvs48/45 and selected fragments in non-human primates. Furthermore, the 3D structure data of the protein(s) will be obtained by physico-chemical analyses [circular dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopies and mass spectrometry (MS) analysis], and bioinformatics and molecular modeling. Natural Abs induced in individuals exposed to P. vivax and P. falciparum in endemic areas of Colombia, Brazil and Burkina Faso will be assessed by ELISA and T-cell responses by flow cytometry. Sera and affinity purified IgG will be tested for TB capacity in MFAs. Furthermore, immunogenicity studies in mice and monkeys will address the potential cross prime/boost effect of parasite infection on Ab response elicited by immunization and vice versa. Potential cross-reactivity of elicited Abs against P. falciparum will be also tested. All facilities and techniques required are available and routinely conducted by the participant groups. At the end of the study we expect to have identified the optimal conditions for Pvs48/45 to induce effective TB immunity in humans and animals and the best vaccine formulations for further clinical development.

 描述（由申请人提供）：在流行地区持续接触疟疾感染的个体会产生免疫反应，这种反应已被证明可以减少或阻止寄生虫从患者传播到蚊子媒介，这就是所谓的传播阻断（TB）免疫。针对配子细胞、受精卵和动合子阶段表达的特定疟原虫抗原的抗体 (Abs) 可以诱导这种阻断，为开发结核病疫苗提供基础。 P48/45 是一种在所有疟原虫物种中表达的保守蛋白，是寄生虫受精所需的，目前正在开发作为恶性疟原虫的候选疫苗，在大肠杆菌中克隆并表达为约 60kDa 的重组体。该产品已被证明具有高度抗原性和免疫原性，接触间日疟原虫的个体会产生针对 Pvs48/45 的抗体，该抗体以年龄依赖性方式增加。具有较高 a-Pvs48/45 Ab 滴度的个体也表现出较高的离体结核活性。初步研究表明，rPvs48/45 蛋白在小鼠和猴子中均具有高度免疫原性，并且所产生的抗体具有离体阻断寄生虫传播的能力。总之，所有这些数据使 Pvs48/45 成为非常有前途的结核病候选疫苗。该提案的目标是确定 rPvs48/45 用于人类的疫苗潜力。我们将使用来自流行地区的个体的血清和细胞以及rPvs48/45结构域和合成肽来进一步表征rPvs48/45的抗原性以绘制相关的免疫和功能表位此外，我们将确认并进一步表征全长的免疫原性。 Pvs48/45 和非人类灵长类动物中的选定片段此外，将通过物理化学分析获得蛋白质的 3D 结构数据。 [圆二色性 (CD) 和核磁共振 (NMR) 光谱和质谱 (MS) 分析]，以及在哥伦比亚、巴西流行地区暴露于间日疟原虫和恶性疟原虫的个体中诱导的天然抗体。和布基纳法索将通过 ELISA 进行评估，并通过流式细胞术评估 T 细胞反应，并测试 MFA 中的 TB 容量。小鼠和猴子的免疫原性研究将解决寄生虫感染对免疫引起的抗体反应的潜在交叉引发/增强作用，反之亦然。还将测试所引起的针对恶性疟原虫的抗体的潜在交叉反应性。在研究结束时，我们希望能够确定 Pvs48/45 在人类和动物中诱导有效结核病免疫的最佳条件，以及用于进一步临床开发的最佳疫苗配方。