Wang Xiang-Yu, Huang Zhao-Xia, Chen Yi-Guo, Lu Xiao, Zhu Ping, Wen Kun, Fu Ning, Liu Bei-Yi
Department of Immunology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong, People's Republic of China.
Laboratory of Emerging Infectious Diseases and Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China.
PLoS One. 2015 Aug 28;10(8):e0136888. doi: 10.1371/journal.pone.0136888. eCollection 2015.
Due to the enormous capacity of Staphylococcus aureus to acquire antibiotic resistance, it becomes imperative to develop vaccines for decreasing the risk of its life-threatening infections. Peptidoglycan (PGN) is a conserved and major component of S. aureus cell wall. However, it has not been used as a vaccine candidate since it is a thymus-independent antigen. In this study, we synthesized a multiple antigenic peptide, named MAP27, which comprised four copies of a peptide that mimics the epitope of PGN. After immunization with MAP27 five times and boosting with heat-inactivated bacterium one time, anti-MAP27 serum bound directly to S. aureus or PGN. Immunization with MAP27 decreased the bacterial burden in organs of BALB/c mice and significantly prolonged their survival time after S. aureus lethal-challenge. The percentage of IFN-γ(+)CD3(+) T cells and IL-17(+)CD4(+) T cells in spleen, as well as the levels of IFN-γ, IL-17A/F and CCL3 in spleen and lung, significantly increased in the MAP27-immunized mice after infection. Moreover, in vitro incubation of heat-inactivated S. aureus with splenocytes isolated from MAP27-immunized mice stimulated the production of IFN-γ and IL-17A/F. Our findings demonstrated that MAP27, as a thymus-dependent antigen, is efficient at eliciting T cell-mediated responses to protect mice from S. aureus infection. This study sheds light on a possible strategy to design vaccines against S. aureus.
由于金黄色葡萄球菌获得抗生素耐药性的能力极强,因此开发疫苗以降低其危及生命的感染风险变得势在必行。肽聚糖(PGN)是金黄色葡萄球菌细胞壁的一种保守且主要的成分。然而,由于它是一种非胸腺依赖性抗原,尚未被用作候选疫苗。在本研究中,我们合成了一种名为MAP27的多抗原肽,它由四个模仿PGN表位的肽拷贝组成。用MAP27免疫五次并用热灭活细菌加强免疫一次后,抗MAP27血清可直接与金黄色葡萄球菌或PGN结合。用MAP27免疫可降低BALB/c小鼠器官中的细菌载量,并显著延长其在金黄色葡萄球菌致死性攻击后的存活时间。感染后,MAP27免疫小鼠脾脏中IFN-γ(+)CD3(+) T细胞和IL-17(+)CD4(+) T细胞的百分比,以及脾脏和肺中IFN-γ、IL-17A/F和CCL3的水平显著升高。此外,用热灭活的金黄色葡萄球菌与从MAP27免疫小鼠分离的脾细胞进行体外孵育,可刺激IFN-γ和IL-17A/F的产生。我们的研究结果表明,MAP27作为一种胸腺依赖性抗原,在引发T细胞介导的反应以保护小鼠免受金黄色葡萄球菌感染方面是有效的。这项研究为设计抗金黄色葡萄球菌疫苗的可能策略提供了思路。