Enhancing DNA vaccines using modified Cholera Toxin A1 Subunit as an adjuvant

描述（由申请人提供）：与传统疫苗相比，使用质粒DNA进行疫苗接种具有提高安全性和有效性的潜力，具有更高的稳定性，并加速产品开发。不幸的是，用DNA接种灵长类动物需要使用过大剂量的质粒进行多次接种。霍乱毒素（CTA1）的A1结构域和相关的热不稳定肠毒素（LTA1）作为佐剂已显示出特别的前景，可以增强小动物DNA疫苗的免疫原性，并可能在灵长类动物中提供必要的剂量节约效应。然而，为了最大限度地利用这一前景，应该提高CTA1或LTA1在体内的活性。我们的目标是确定CTA1或LTA1的修饰，以增强它们在

DESCRIPTION (provided by applicant): Vaccination using plasmid DNA has the potential to provide enhanced safety and efficacy over conventional vaccines with increased stability, and accelerated product development. Unfortunately, vaccination of primates with DNA requires multiple inoculations using excessively large doses of plasmid. The A1 domains of cholera toxin (CTA1) and the related heat-labile enterotoxin (LTA1) have demonstrated particular promise as adjuvants that can enhance the immunogenicity of DNA vaccines in small animals and may provide a necessary dose sparing effect in primates. To maximally exploit this promise, however, the activity of CTA1 or LTA1 in vivo should be improved. Our objective is to identify modifications to CTA1 or LTA1 that will enhance their activity in vivo by pursuing the following aims: Aim 1: Identify mutations in the active site of either CTA1 or LTA1 that enhance enzymatic activity in vitro; Aim 2: Identify fusion constructs between CTA1 or LTA1 and human ARF6 that enhance enzymatic activity in vitro; and, Aim 3: Identify constructs from Aims 1, and 2 that optimally enhance the immunogenicity of a candidate SIMmac239-gag DNA vaccine in vivo. Candidate constructs that display a minimum of 10-fold enhanced adjuvanticity in vivo will be selected for evaluation in primate studies to be proposed in phase 2. Successful candidates in phase 2 will be incorporated into candidate HIV DNA vaccines intended for clinical evaluation.