GP350 AS A NOVEL VACCINE PROTEIN CARRIER

GP350 作为新型疫苗蛋白载体

• 批准号: 7349607
• 负责人: CLIFFORD M SNAPPER
• 金额: $ 3.5万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7349607
• 关键词: GP350; NOVEL; VACCINE; PROTEIN; CARRIER; GP350; NOVEL; VACCINE; PROTEIN; CARRIER

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Purpose of the experiment: gp350 is an Epstein-Barr virus (EBV) protein that binds to CD21 on human and monkey, but not mouse, B cells. Previous studies have demonstrated that the co-crosslinking of CD21 and the B cell antigen receptor (BCR) on the surface of the B cell is highly synergistic for B cell activation and significantly lowers the amount of antigen required for optimal immunogenicity. CD21 is also expressed on follicular dendritic cells (FDC), present within germinal centers, where it is used to trap antigen (via bound complement) on the surface of the FDC and thus augment the germinal center reaction and subsequent immunity. A recent study demonstrated that linkage of C3d to a polysaccharide antigen leads to improved anti-polysaccharide responses in vivo. Thus, we propose that gp350 can be used as a novel carrier protein for polysaccharide conjugate vaccines in which gp350 not only serves to recruit T cell help (on the basis of it being a foreign protein) for the anti-polysaccharide response but provides an adjuvanting affect as well (on the basis of its ability to bind CD21), potentially allowing for the use of much lower doses of antigen in vivo. Further, we are constructing a dimer of gp350 that can be conjugated to peptides or proteins and used in a similar fashion to augment anti-peptide or anti-protein Ig responses. Preparation of conjugates: We have covalently linked gp350 to pneumococcal capsular polysaccharide, serotype 14 (PPS14). As a control we use the same chemistry and conjugation conditions to produce a similar conjugate of diphtheria toxoid (DT) covalently linked to PPS14. Further, we confirmed that the gp350-PPS14 conjugate retained its binding activity to CD21, using a CD21-expressing cell line. We also demonstrated that both conjugates are immunogenic in mice for both the anti-PPS14 and anti-protein response. Finally, we confirmed that the gp350 also specifically binds to peripheral blood B cells derived from either Cynomolgus or rhesus monkeys. Goals of current experiment: The goal of this initial experiment is a PROOF of PRINCIPLE, and are to directly compare the two conjugates using what historically should be optimal doses of antigen. This will give us baseline data that we can indeed elicit specific Ig responses in monkeys using these conjugates and to directly compare the quantitative responses between these two conjugates.

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子弹和调查员（PI）可能已经从其他NIH来源获得了主要资金，因此可以在其他清晰的条目中代表。列出的机构适用于该中心，这不一定是调查员的机构。实验的目的：GP350是一种爱泼斯坦 - 巴尔病毒（EBV）蛋白，在人和猴子上与CD21结合，而不是小鼠B细胞。先前的研究表明，B细胞表面上CD21和B细胞抗原受体（BCR）的共链接具有高度协同的B细胞激活，并且显着降低了最佳免疫原性所需的抗原量。 CD21还以生发中心内存在于卵泡树突状细胞（FDC）上表达，在该中心内，它用于在FDC表面捕获抗原（通过结合补体），从而增强生发中心反应以及随后的免疫力。最近的一项研究表明，C3D与多糖抗原的连接会导致体内改善的抗糖糖反应。因此，我们建议GP350可以用作多糖共轭疫苗的新型载体蛋白，其中GP350不仅可以募集T细胞帮助（根据外国蛋白质）来抗抗糖糖反应，而且还提供了辅助性影响（基于其允许cd21的能力），可以降低允许cd21的能力。此外，我们正在构建一个GP350的二聚体，该二聚体可以与肽或蛋白质结合，并以类似的方式用于增强抗肽或抗蛋白质Ig反应。 共轭物的制备：我们将GP350与肺炎球菌囊多糖，血清型14（PPS14）联系起来。作为对照，我们使用相同的化学和结合条件来产生与PPS14共价链接的类似的白喉毒素（DT）。此外，我们确认GP350-PPS14结合物使用表达CD21的细胞系保留了与CD21的结合活性。我们还证明了抗PPPS14和抗蛋白质反应的小鼠中两个结合物都是免疫原性的。最后，我们确认GP350还特别结合了源自cynomolgus或恒河猴的外周血B细胞。 当前实验的目标：该初始实验的目标是原理的证明，并将使用历史上应成为最佳抗原的最佳剂量直接比较两个偶联物。这将为我们提供基线数据，我们确实可以使用这些共轭物在猴子中引起特定的Ig响应，并直接比较这两个共轭物之间的定量响应。