Antigenicity and Immunogenicity of Stabilized prefusion F protein

RSV F糖蛋白是疫苗诱导的中和抗体的关键靶点。我们的假设是，通过定义F的结构和与中和相关的表位结构，将有助于理解抗体中和的机制。这将允许设计新的抗原。表征F的化学性质和翻译后修饰也将促进改进疫苗抗原设计。我们已经在VRC 317一期临床试验中对我们的稳定预灌注F蛋白进行了临床评估。在这项试验中，我们正在评估我们的稳定预灌注F蛋白（DS-Cav1）与明矾佐剂或与明矾佐剂在健康成人中的安全性、耐受性和免疫原性。我们已经评估了人类对单剂量DS-Cav1的免疫反应，发现接种DS-Cav1可使中和活性增加7-15倍。对抗体反应的解剖表明，DS-Cav1免疫既能诱导结合该蛋白预融合形态的抗体，也能诱导结合该蛋白预融合形态和融合后形态的抗体。接种DS-Cav1引起的中和活性高于RSV感染引起的中和活性，比F后或不确定F结构引起的中和活性高2-5倍。这项工作为基于结构的疫苗设计提供了临床概念验证。

The RSV F glycoprotein is a key target for vaccine-induced neutralizing antibody. Our hypothesis is that understanding the mechanism of antibody neutralization will be facilitated by defining the structure of F and the structure of epitopes associated with neutralization. This will allow novel antigen design. Characterizing the chemistry and post-translational modifications in F will also promote improved vaccine antigen design. We have tested our stabilized prefusion F protein into clinical evaluation in a Phase 1 clinical trial, VRC 317. In this trial, we are evaluating safety, tolerability, and immunogenicity of our stabilized prefusion F protein (DS-Cav1) with or with alum adjuvant in healthy adults. We have assessed the immune response to a single dose of DS-Cav1 in humans and found that DS-Cav1 vaccination elicits a 7-15-fold increase in neutralizing activity. Dissection of the antibody response showed that DS-Cav1 immunization elicited both antibodies that bind to the prefusion form of the protein and antibodies that bind to both the prefusion and postfusion conformation. The neutralizing activity elicited by DS-Cav1 vaccination is higher than that elicited by RSV infection, and 2-5 fold higher than neutralizing activity elicited by post-F or non-determined F structure. This work serves as a clinical proof-of-concept for structure-based vaccine design. In addition to neutralizing antibodies, the induction of both protective, disease-sparing CD8+ T cell responses are desirable in a vaccine candidate. These studies include evaluation of gene and vector-based vaccines expressing either the stabilized Pre-F protein or the wildtype F protein to vaccination with soluble Pre-F protein. We are also working with collaborators to assess immunogenicity of other vectors expressing our stabilized Pre-F protein.