Iwasaki Taro, Hirano Takashi, Kodama Satoru, Kadowaki Yoshinori, Moriyama Munehito, Kawano Toshiaki, Suzuki Masashi
Department of Otolaryngology, Faculty of Medicine, Oita University, Oita 879-5503, Japan.
Department of Otolaryngology, Faculty of Medicine, Oita University, Oita 879-5503, Japan.
Int J Pediatr Otorhinolaryngol. 2017 Jun;97:5-12. doi: 10.1016/j.ijporl.2017.03.018. Epub 2017 Mar 19.
Acute otitis media (AOM) is one of the most common infectious diseases in children. Nontypeable Haemophilus influenzae (NTHi) is Gram-negative bacteria that are considered major pathogens of AOM and respiratory tract infections. In this study, we used monophosphoryl lipid A (MPL), a toll-like receptor (TLR) 4 agonist, as an adjuvant to induce mucosal immune responses against NTHi to enhance bacterial clearance from the nasopharynx.
Mice were administered 10 μg outer membrane protein (OMP) from NTHi and 0, 10, or 20 μg MPL intranasally once a week for 3 weeks. Control mice were administered phosphate-buffered saline alone. After immunization, these mice were challenged with NTHi. At 6 and 12 h after bacterial challenge, the mice were killed and nasal washes and sera were collected. The numbers of NTHi- and OMP-specific antibodies were quantified by enzyme-linked immunosorbent assay.
The MPL 10 and 20 μg group produced a significant reduction in the number of bacteria recovered from the nasopharynx at 12 h after bacterial challenge compared to the control group. OMP-specific IgA titers were also augmented in the MPL groups compared to the control and OMP groups.
MPL is suitable for eliciting effective mucosal immune responses against NTHi in the nasopharynx. These results demonstrate the possibility of an adjuvant that involves stimulation of the innate immune system by TLR4 agonists such as MPL for mucosal vaccination.
急性中耳炎（AOM）是儿童最常见的传染病之一。不可分型流感嗜血杆菌（NTHi）是革兰氏阴性菌，被认为是AOM和呼吸道感染的主要病原体。在本研究中，我们使用单磷酰脂质A（MPL），一种Toll样受体（TLR）4激动剂，作为佐剂来诱导针对NTHi的黏膜免疫反应，以增强从鼻咽部清除细菌的能力。
给小鼠每周一次经鼻内给予10μg NTHi的外膜蛋白（OMP）以及0、10或20μg MPL，共3周。对照小鼠仅给予磷酸盐缓冲盐水。免疫后，用NTHi攻击这些小鼠。在细菌攻击后6小时和12小时，处死小鼠并收集鼻腔灌洗液和血清。通过酶联免疫吸附测定法定量NTHi特异性抗体和OMP特异性抗体的数量。
与对照组相比，MPL 10μg组和20μg组在细菌攻击后12小时从鼻咽部回收的细菌数量显著减少。与对照组和OMP组相比，MPL组的OMP特异性IgA滴度也有所增加。
MPL适用于在鼻咽部引发针对NTHi的有效黏膜免疫反应。这些结果证明了一种佐剂的可能性，该佐剂涉及通过TLR4激动剂如MPL刺激先天性免疫系统进行黏膜疫苗接种。
