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: 9007904
• 负责人: Myriam Arevalo-Herrera
• 金额: $ 41.68万
• 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/9007904
• 关键词: Address; Adjuvant; Affinity; Affinity Chromatography; Age; Alhydrogel; Animals; Anopheles Genus; Antibodies; Antibody Formation; Antibody Response; Antibody Specificity; Antigens; Area; B-Lymphocytes; Bioinformatics; Biological Assay; Biophysics; Blocking Antibodies; Blood; Brazil; Burkina Faso; Cells; Chemicals; Circular Dichroism; Clinical; Colombia; Colombian; Cross-Priming; Culicidae; Data; Development; Disease; Enzyme-Linked Immunosorbent Assay; Epidemiology; Epitopes; Escherichia coli; Fertilization; Flow Cytometry; Goals; Health; Human; Immune; Immune response; Immunity; Immunization; Immunoglobulin G; Individual; Infection; Lead; Length; Location; Malaria; Maps; Mass Spectrum Analysis; Measures; Methods; Modeling; Molecular Models; Monkeys; Montanide ISA-51; Mus; N-terminal; 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; Serum; Staging; T cell response; T-Cell Proliferation; T-Lymphocyte Epitopes; Techniques; Tertiary Protein Structure; Testing; Vaccination; Vaccine Design; Vaccines; age related; base; cost effective; cross reactivity; cytokine; design; domain mapping; experience; immunogenic; immunogenicity; malaria infection; malaria transmission; molecular modeling; nonhuman primate; pre-clinical; preclinical study; prevent; protein folding; structural biology; synthetic peptide; three dimensional structure; transmission process; transmission-blocking vaccine; vaccine candidate; vaccine development; 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 α-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（由适用提供）：内在区域中不断暴露于疟疾感染的个体会产生免疫复杂，这些免疫复杂已显示出可减少或阻断从患者到蚊子载体的传播或阻断所谓的传播阻断（TB）免疫史的传播。在这种情况下，靶向在配子细胞，合子和固定阶段表达的特定疟原虫抗原的抗体（ABS）可以诱导这种阻塞，从而为TB疫苗的发展提供了基础。这些抗原之一是P48/45是一种保守的蛋白质，在所有疟原虫种类中表达，寄生虫受精所需，目前正在作为恶性疟原虫的疫苗候选。在大肠杆菌中克隆并表达的Vivax直系同源物，作为约60kDa重组产物，已显示出高度抗原和免疫原性。暴露于Vivax的个体对PVS48/45产生ABS，而PVS48/45以年龄依赖的方式增加，而具有较高α-PVS48/45 AB滴度的个体也表现出较高的外体TB活性。试点研究表明，RPVS48/45蛋白在小鼠和猴子中都具有高度免疫原性，并且ABS被引起的能力具有离体阻断寄生虫传播到蚊子的能力。所有这些数据一起使PVS48/45成为非常有前途的结核病疫苗候选者。该提案的目的是确定RPVS48/45的疫苗潜力用于人类使用。我们将进一步表征使用内在区域的血清和个体的RPVS48/45的抗原性，以及RPVS48/45域和合成肽的抗原性，以绘制相关的免疫原性和功能性表位。此外，我们将确认并进一步表征全长PVS48/45的免疫原性以及非人类隐私的选定片段。此外，蛋白质的3D结构数据将通过物理化学分析[圆二色性（CD）和核磁共振（NMR）光谱法（MS）分析（MS）分析]以及生物信息学和分子建模获得。暴露于哥伦比亚，巴西和布基纳FASO内人体区域中暴露于Vivax和恶性疟原虫的个体中的天然ABS将通过ELISA和流式细胞仪来评估ELISA和T细胞反应。血清和亲和力纯化的IgG将测试MFA中的结核病能力。此外，小鼠和猴子的免疫原性研究将解决寄生虫感染对免疫化引起的AB反应的潜在交叉质量/增强作用，反之亦然。还将测试引起的ABS针对恶性疟原虫的潜在交叉反应性。所需的所有设施和技术都可以由参与小组提供并经常进行。在研究结束时，我们希望已经确定了PVS48/45的最佳条件，以诱导人类和动物的有效结核病免疫，以及最佳的疫苗配方，用于进一步的临床发育。