Barrett D J
Adv Pediatr. 1985;32:139-58.
Mechanisms of human immunity to polysaccharide encapsulated bacteria and the development and testing of the currently available purified polysaccharide bacterial vaccines are reviewed. These vaccines appear to be poorly immunogenic in infants under the age of two years--those at greatest risk for infection. In an effort to understand the poor responses of infants, the human immune response to polysaccharide antigens was characterized in more detail. Using pneumococcal polysaccharide type 3 as an example, it appears that human polysaccharide antibody responses are analogous to the type 2 T cell independent responses defined in the murine system. These studies suggest that the deficient polysaccharide response of human infants is due to a deficiency in maturation of distinct B lymphocyte subpopulations, as well as imbalanced T regulatory influences. The development of vaccines containing the purified capsular polysaccharides of S. pneumoniae, H.influenzae, and N. meningitidis during the past decade offered promise for the prevention of the major causes of bacterial sepsis and meningitis during childhood. The fulfillment of that promise was thwarted by the unrecognized complexities of human antibody responses to polysaccharide antigens. Continued vigorous research in this area has led us to a better understanding of the cellular requirements and immunoregulation of human polysaccharide antibody responses and has given us a clear direction for the pursuit of an effective means for immunization of infants.
本文综述了人类对多糖包膜细菌的免疫机制以及目前可用的纯化多糖细菌疫苗的研发和测试情况。这些疫苗在两岁以下的婴儿（即感染风险最高的人群）中似乎免疫原性较差。为了了解婴儿反应不佳的原因，对人类对多糖抗原的免疫反应进行了更详细的研究。以3型肺炎球菌多糖为例，人类多糖抗体反应似乎类似于在小鼠系统中定义的2型非T细胞依赖性反应。这些研究表明，人类婴儿多糖反应不足是由于不同B淋巴细胞亚群成熟不足以及T调节影响失衡所致。在过去十年中，含有肺炎链球菌、流感嗜血杆菌和脑膜炎奈瑟菌纯化荚膜多糖的疫苗的研发为预防儿童期细菌性败血症和脑膜炎的主要病因带来了希望。人类对多糖抗原的抗体反应存在未被认识的复杂性，这使得这一希望受挫。该领域持续的积极研究使我们对人类多糖抗体反应的细胞需求和免疫调节有了更好的理解，并为我们寻求有效的婴儿免疫方法指明了明确的方向。
