Department of Pathology and Laboratory Medicine, Medical Sciences I, Room D440, University of California, Irvine, Irvine, CA 92697-4800, USA.
C.N.R.S./Université Paris-7 UMR 7099, Institut de Biologie Physico-Chimique, 13, rue Pierre-et-Marie-Curie, F-75005 Paris, France.
Vaccine. 2018 Oct 29;36(45):6640-6649. doi: 10.1016/j.vaccine.2018.09.055. Epub 2018 Oct 4.
Chlamydial infections are spread worldwide and a vaccine is needed to control this pathogen. The goals of this study were to determine if the delivery of an adjuvant associated to the antigen, via a derivatized amphipol, and adjuvant combinations improve vaccine protection.
A novel approach, trapping the Chlamydia muridarum (Cm) native MOMP (nMOMP) with amphipols (A8-35), bearing a covalently conjugated peptide (EP67), was used. Adjuvants incorporated were: EP67 either conjugated to A8-35, which was used to trap nMOMP (nMOMP/EP67-A8-35), or free as a control, added to nMOMP/A8-35 complexes (nMOMP/A8-35+EP67); Montanide ISA 720 to enhance humoral responses, and CpG-1826 to elicit robust cell-mediated immunity (CMI). BALB/c mice were immunized by mucosal and systemic routes. Intranasal immunization with live Cm was used as positive control and three negative controls were included. Mice were challenged intranasally with Cm and changes in body weight, lungs weight and number of Cm-inclusion forming units (IFU) recovered from the lungs were evaluated to establish protection. To assess local responses levels of IFN- γ and Cm-specific IgA were determined in lungs' supernatants.
Structural assays demonstrated that nMOMP secondary structure and thermal stability were maintained when A8-35 was covalently modified. Mice vaccinated with nMOMP/EP67-A8-35 were better protected than animals immunized with nMOMP/A8-35+EP67. Addition of Montanide enhanced Th2 responses and improved protection. Including CpG-1826 further broadened, intensified and switched to Th1-biased immune responses. With delivery of nMOMP and the three adjuvants, as determined by changes in body weight, lungs weight and number of IFU recovered from lungs, protection at 10 days post-challenge was equivalent to that induced by immunization with live Cm.
Covalent association of EP67 to A8-35, used to keep nMOMP water-soluble, improves protection over that conferred by free EP67. Adjuvant combinations including EP67+Montanide+CpG-1826, by broadening and intensifying cellular and humoral immune responses, further enhanced protection.
衣原体感染在全球范围内传播，需要疫苗来控制这种病原体。本研究的目的是确定通过衍生的两亲聚合物将抗原与佐剂共同传递，以及佐剂组合是否能提高疫苗的保护作用。
采用一种新方法，用两亲聚合物（A8-35）捕获沙眼衣原体（Cm）天然主要外膜蛋白（nMOMP），并共价连接一个肽（EP67）。所使用的佐剂包括：EP67 要么与 A8-35 结合，用于捕获 nMOMP（nMOMP/EP67-A8-35），要么作为对照自由添加到 nMOMP/A8-35 复合物中（nMOMP/A8-35+EP67）；Montanide ISA 720 增强体液免疫应答，CpG-1826 激发强大的细胞介导免疫应答（CMI）。BALB/c 小鼠通过黏膜和全身途径进行免疫接种。鼻腔内接种活 Cm 作为阳性对照，同时包括三个阴性对照。通过鼻腔内感染 Cm 来评估小鼠的保护作用，观察体重、肺部重量和从肺部回收的 Cm 包涵体形成单位（IFU）数量的变化。为了评估局部反应水平，测定了肺部上清液中 IFN-γ和 Cm 特异性 IgA 的水平。
结构分析表明，当 A8-35 发生共价修饰时，nMOMP 的二级结构和热稳定性得以维持。与接种 nMOMP/A8-35+EP67 的小鼠相比，接种 nMOMP/EP67-A8-35 的小鼠得到了更好的保护。添加 Montanide 增强了 Th2 反应并提高了保护效果。加入 CpG-1826 进一步扩大、增强并转向 Th1 偏向的免疫反应。通过检测体重、肺部重量和从肺部回收的 IFU 数量的变化，用 nMOMP 和三种佐剂进行免疫接种，其保护效果与用活 Cm 免疫接种相当。
将 EP67 共价结合到 A8-35 上，用于保持 nMOMP 的水溶性，可提高游离 EP67 的保护作用。包括 EP67+Montanide+CpG-1826 的佐剂组合通过扩大和增强细胞和体液免疫反应，进一步增强了保护作用。
