ABSTRACT

Introduction: Nasopharyngeal colonization is a precondition for mucosal and invasive pneumococcal disease. Prevention of colonization may reduce pneumococcal transmission and disease incidence. Therefore, several protein-based pneumococcal vaccines are currently under investigation.

Areas covered: We aimed to better understand the host immune responses to pneumococcal proteins in the upper respiratory tract (URT) that could facilitate the development of serotype-independent pneumococcal vaccines. English peer-reviewed papers reporting immunological mechanisms involved in host immune response to pneumococcal proteins in the URT were retrieved through a PubMed search using the terms ‘pneumococcal proteins,’ ‘nasopharyngeal colonization’ and/or ‘cellular/humoral host immune response.’

Expert opinion: Although pneumococcal protein antigens induce humoral immune responses, as well as IL-17A-mediated immunity, none of them, when used as single antigen, is sufficient to control and broadly protect against pneumococcal colonization. Novel vaccines should contain multiple conserved protein antigens to activate both arms of the immune system and evoke protection against the whole spectrum of pneumococcal variants by reducing, rather than eradicating, pneumococcal carriage. The highest efficacy would likely be achieved when the vaccine is intranasally applied, inducing mucosal immunity and enhancing the first line of defense by restricting pneumococcal density in the URT, which in turn will lead to reduced transmission and protection against disease.

摘要

介绍

鼻咽部定植是粘膜和浸润性肺炎球菌疾病的前提。因此，预防定植可减少肺炎球菌传播和疾病发生率。因此，目前正在研究几种基于蛋白质的肺炎球菌疫苗。

覆盖区域

目的是更好地了解宿主对上呼吸道（URT）中肺炎球菌蛋白的免疫反应，这可以促进不依赖血清型的肺炎球菌疫苗的开发。通过PubMed搜索，使用术语“肺炎球菌蛋白”，“鼻咽定植”和/或“细胞和体液宿主免疫应答”，检索了一篇发表于英语的同行评审论文，这些论文报道了URT中针对肺炎球菌蛋白的宿主免疫应答所涉及的免疫机制。

专家意见

几项研究表明，尽管肺炎球菌蛋白抗原可诱导体液免疫反应以及IL-17A介导的免疫，但它们均不能用作单一抗原，足以控制并广泛预防肺炎球菌的定殖。新型疫苗应包含多种保守的蛋白抗原，以激活免疫系统的两臂，并通过减少而不是消除肺炎球菌的携带而对整个肺炎球菌变种起保护作用。当鼻内应用疫苗时，通过限制URT中的肺炎球菌密度，诱导粘膜免疫并增强一线防御力，可能会达到最高功效，进而导致传播减少和疾病防护。