Respiratory tract coinfections, specifically involving influenza A virus (IAV) and Streptococcus pneumoniae (S. pneumoniae), remain a major health problem worldwide. Secondary bacterial pneumonia is a common complication and an important cause of mortality related to seasonal and pandemic influenza infections. Vaccination is a basic control strategy against influenza and S. pneumoniae. The fusion protein DnaJ-ΔA146Ply is a vaccine candidate which can induce immune responses against pneumococcal infections via mucosal and subcutaneous immunization in mice. In the present study, we established a co-infection model using mouse-adapted laboratory strains of IAV (PR8) and S. pneumoniae (19F) in mice intranasally and subcutaneously immunized with DnaJ-ΔA146Ply. Our results showed that vaccinated mice suffered decreased weight loss compared with control mice. The survival rates were higher in intranasally and subcutaneously immunized mice than in control mice. In addition, the bacterial loads in nasal washes and lung homogenates were lower in vaccinated mice than in control mice. Furthermore, lung damage was alleviated in vaccinated mice compared with control mice, with less broken alveoli and less proinflammatory cytokine production. Taken together, these results indicate that vaccination with DnaJ-ΔA146Ply shows protective potential against influenza and S. pneumoniae co-infection in mice.

呼吸道合并感染，特别是甲型流感病毒 (IAV) 和肺炎链球菌( S. 肺炎)，仍然是世界范围内的主要健康问题。继发性细菌性肺炎是一种常见的并发症，也是与季节性和大流行性流感感染相关的重要死亡原因。疫苗接种是针对流感和肺炎链球菌的基本控制策略。融合蛋白 DnaJ-ΔA146Ply 是一种候选疫苗，可通过小鼠的粘膜和皮下免疫诱导针对肺炎球菌感染的免疫反应。在本研究中，我们使用 IAV (PR8) 和肺炎链球菌的小鼠适应实验室菌株建立了一个共感染模型。(19F) 在用 DnaJ-ΔA146Ply 鼻内和皮下免疫的小鼠中。我们的结果表明，与对照小鼠相比，接种疫苗的小鼠体重减轻减少。鼻内和皮下免疫小鼠的存活率高于对照小鼠。此外，接种疫苗的小鼠鼻腔冲洗液和肺匀浆中的细菌负荷低于对照小鼠。此外，与对照小鼠相比，接种疫苗的小鼠肺损伤得到缓解，肺泡破裂更少，促炎细胞因子产生更少。总之，这些结果表明用 DnaJ-ΔA146Ply 接种疫苗显示出对小鼠流感和肺炎链球菌合并感染的保护潜力。