Department of Infectious Disease Epidemiology, Imperial College London, London W2 1PG, United Kingdom.
Infection Genomics Programme, Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom; email:
Annu Rev Microbiol. 2018 Sep 8;72:521-549. doi: 10.1146/annurev-micro-090817-062338.
Streptococcus pneumoniae (the pneumococcus) is a nasopharyngeal commensal and respiratory pathogen. Most isolates express a capsule, the species-wide diversity of which has been immunologically classified into ∼100 serotypes. Capsule polysaccharides have been combined into multivalent vaccines widely used in adults, but the T cell independence of the antibody response means they are not protective in infants. Polysaccharide conjugate vaccines (PCVs) trigger a T cell-dependent response through attaching a carrier protein to capsular polysaccharides. The immune response stimulated by PCVs in infants inhibits carriage of vaccine serotypes (VTs), resulting in population-wide herd immunity. These were replaced in carriage by non-VTs. Nevertheless, PCVs drove reductions in infant pneumococcal disease, due to the lower mean invasiveness of the postvaccination bacterial population; age-varying serotype invasiveness resulted in a smaller reduction in adult disease. Alternative vaccines being tested in trials are designed to provide species-wide protection through stimulating innate and cellular immune responses, alongside antibodies to conserved antigens.
肺炎链球菌（肺炎球菌）是一种鼻咽共生菌和呼吸道病原体。大多数分离株表达荚膜，其物种多样性已通过免疫学分类为约 100 种血清型。荚膜多糖已被组合成多价疫苗，广泛用于成年人，但抗体反应的 T 细胞独立性意味着它们对婴儿没有保护作用。多糖结合疫苗（PCV）通过将载体蛋白附着在荚膜多糖上来触发 T 细胞依赖性反应。PCV 在婴儿中引起的免疫反应抑制了疫苗血清型（VTs）的携带，从而在人群中产生了群体免疫力。这些被非 VTs 取代。然而，PCVs 通过降低接种后细菌种群的平均侵袭性，减少了婴儿的肺炎球菌疾病，由于接种后细菌种群的年龄相关血清型侵袭性，成年人疾病的减少幅度较小。正在临床试验中测试的替代疫苗旨在通过刺激先天和细胞免疫反应以及针对保守抗原的抗体来提供全物种保护。
