Alteration of lipid A acyl chain length in Salmonella

描述（由申请人提供）：重组减毒沙门氏菌疫苗（rasv）是一种有效且廉价的方法，可引起强烈的粘膜和体液免疫反应。然而，该领域的一个问题是，虽然rasv在动物模型中是减毒的和安全的，但当给人使用时，它们可能是反应性的，产生不必要的副作用，包括腹泻、腹痛、胃肠道紊乱、神经系统紊乱和发烧。许多这些症状与已知的脂质A反应一致。脂质A通过toll样受体4 （TLR4）与人体免疫系统相互作用，TLR4可识别与脂质A相关的特定部分，包括酰基链。酰基链的长度和数量影响脂质A: TLR4相互作用的强度和结果。为了减少活细菌疫苗的潜在内毒作用，我们将研究修改活沙门氏菌细胞中酰基链长度的影响。我们的目标是通过改变脂质A酰基链的长度来降低脂质A的总体毒性，而不影响整体免疫原性。我们将构建一系列脂质A酰基链长度不同的沙门氏菌突变体，并评估和比较它们在野生型背景下的毒力和引发先天免疫的能力。不影响毒力或定殖能力的酰化修饰将随后在沙门氏菌疫苗中进行评估，以确定其

DESCRIPTION (provided by applicant): Recombinant attenuated Salmonella vaccines (RASVs) are an effective and inexpensive way to elicit strong mucosal and humoral immune responses. However, one problematic issue in this field has been that while RASVs are attenuated and safe in animal models, when administered to humans they can be reactogenic, producing unwanted side effects, including diarrhea, abdominal pain, gastrointestinal disorder, nervous system disorders, and fever. Many of these symptoms are consistent with known reactions to lipid A. Lipid A interacts with the human immune system via the toll-like receptor 4 (TLR4) which recognizes specific moieties associated with lipid A, including the acyl chains. The length and number of acyl chains influences the strength and outcome of the lipid A: TLR4 interaction. In an effort to reduce the potential for endotoxic effects in live bacterial vaccines,we will investigate the effects of modifying the acyl chain length in living Salmonella cells. Our goa is to reduce the overall toxicity of lipid A without compromising overall immunogenicity by modifying the length of the acyl chains from lipid A. We will construct a series of Salmonella mutants that differ in lipid A acyl chain length, and evaluate and compare their virulence and ability to elicit innate immunity in wild-type background. Acylation modifications that do not affet virulence or colonization ability will then be evaluated in Salmonella vaccines, to determine their influence on ability to elicit an immune response against a vectored antigen and against challenge. The success of this project could lead to safer and more immunogenic strains for human use.