Staphylococcus aureus (SA), especially the methicillin-resistant variant (MRSA), is becoming a serious threat to human health in hospitals and communities, making the development of an effective vaccine urgent. Alpha-hemolysin (Hla) is a key virulence factor and also a good target for the development of SA vaccines. However, the epitopes in Hla recognized by human immunity are not characterized in detail, which hinders the design of epitope-based human vaccines against SA. In this study, we collected sera from volunteers in a phase 1b clinical trial of a novel recombinant five-antigen SA vaccine (NCT03966040). Using a Luminex-based assay, we characterized the human serologic response against Hla, and identified Hla_121-138 as a neutralizing epitope. In addition, we successfully produced ferritin nanoparticles carrying the neutralizing Hla_121-138 epitope (EpNP) in E. coli. EpNP presented as homogenous nanoparticles in aqueous solution. Immunization with EpNP elicited potent hemolysis-neutralizing antibodies and conferred significant protection in a mouse model of SA skin infection. Our data suggest that EpNP, carrying the neutralizing epitope Hla_121-138, is a good candidate for a vaccine against SA.

金黄色葡萄球菌(SA)，尤其是耐甲氧西林变异体 (MRSA)，正成为医院和社区人类健康的严重威胁，因此迫切需要开发有效的疫苗。α-溶血素 (Hla) 是一种关键的毒力因子，也是开发 SA 疫苗的良好靶点。然而，人类免疫识别的Hla中的表位没有详细表征，这阻碍了基于表位的针对SA的人类疫苗的设计。在这项研究中，我们在新型重组五抗原 SA 疫苗 (NCT03966040) 的 1b 期临床试验中收集了志愿者的血清。使用基于 Luminex 的测定，我们表征了人类对 Hla 的血清学反应，并确定了 Hla _121-138作为中和表位。此外，我们在大肠杆菌中成功生产了携带中和 Hla _121-138表位 (EpNP) 的铁蛋白纳米颗粒。EpNP 在水溶液中表现为均匀的纳米颗粒。使用 EpNP 进行免疫接种会引发有效的溶血中和抗体，并在 SA 皮肤感染小鼠模型中提供显着保护。我们的数据表明，携带中和表位 Hla _{121-138 的 EpNP}是抗 SA 疫苗的良好候选者。