In mice, pneumococcal polysaccharide (PPS) vaccines generate antigen-specific IgM, IgG1, IgG2 and IgG3. Antibody and complement-dependent opsonophagocytosis correlates with the protection induced by PPS vaccines in vivo. Since IgM is a very efficient immunoglobulin isotype in activating the complement system, we evaluated whether anti-PPS IgM alone is sufficient to confer protective immunity to Streptococcus pneumoniae. We found that immunization of wildtype and activation-induced cytidine deaminase-deficient mice capable of producing only IgM with Pneumovax®23 generated comparable anti-PPS IgM and resistance to lethal systemic challenge with S. pneumoniae. These data suggests that an IgM response to PPS vaccines is sufficient for conferring immunity.

中文翻译：

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对肺炎球菌多糖疫苗的 IgM 反应足以赋予免疫力

在小鼠中，肺炎球菌多糖 (PPS) 疫苗会产生抗原特异性 IgM、IgG1、IgG2 和 IgG3。抗体和补体依赖性调理吞噬作用与 PPS 疫苗在体内诱导的保护作用相关。由于 IgM 是激活补体系统的一种非常有效的免疫球蛋白同种型，我们评估了单独的抗 PPS IgM 是否足以赋予对肺炎链球菌的保护性免疫力。我们发现，使用 Pneumovax®23 对只能产生 IgM 的野生型和激活诱导的胞苷脱氨酶缺陷小鼠进行免疫，产生了相当的抗 PPS IgM 和对肺炎链球菌致死性全身攻击的抵抗力。这些数据表明对 PPS 疫苗的 IgM 反应足以赋予免疫力。