Age-dependent preference in human antibody responses to Streptococcus pneumoniae polypeptide antigens
Age-dependent preference in human antibody responses to Streptococcus pneumoniae polypeptide antigens
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DOI：
10.1046/j.1365-2249.2002.01745.x
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发表时间：
2002-02-01
影响因子：
4.6
通讯作者：
Nebenzahl, YM
中科院分区：
文献类型：
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作者：
Lifshitz, S;Dagan, R;Nebenzahl, YM
儿童对肺炎链球菌的易感性最明显。微生物的毒力因子和宿主免疫反应的特点，有助于这一现象还没有完全理解。在目前的研究中，体液免疫反应分离链球菌。肺炎链球菌表面蛋白和干扰链球菌的能力。在成人和儿童中分析了肺炎链球菌与培养的上皮细胞的粘附。从健康成人收集的血清识别链球菌。在Western印迹分析中，肺炎链球菌分离凝集素和非凝集素表面蛋白，并且平均抑制80%的链球菌。pneumoniae对上皮细胞的粘附呈浓度依赖性。然而，从18个月大的日托中心的健康儿童中纵向收集的血清和随后2年的过程显示：（a）以前未被识别的链球菌抗体的发展。肺炎链球菌表面蛋白随年龄的变化;（B）通过光密度测定法测量的针对分离的链球菌的抗体应答的定量增加。肺炎链球菌表面蛋白与年龄的关系;和（c）链球菌的抑制。在18个月龄时平均为50%的肺炎杆菌对上皮细胞的粘附显著增加，在42个月龄时平均抑制水平为80%，等于成人血清抑制值。本研究中获得的结果，来自于纵向收集的健康儿童血清，记录了反复链球菌感染。肺炎链球菌定殖，表明重复暴露不足以引发对链球菌的免疫应答。肺炎蛋白在18个月的年龄。无法识别链球菌。肺炎链球菌表面蛋白的低免疫原性可能源于在该年龄T细胞依赖性B细胞应答的低效率和/或源于蛋白质的低免疫原性。
Vulnerability to Streptococcus pneumoniae is most pronounced in children. The microbial virulence factors and the features of the host immune response contributing to this phenomenon are not completely understood. In the current study, the humoral immune response to separated Strep. pneumoniae surface proteins and the ability to interfere with Strep. pneumoniae adhesion to cultured epithelial cells were analysed in adults and in children. Sera collected from healthy adults recognized Strep. pneumoniae separated lectin and nonlectin surface proteins in Western blot analysis and inhibited on average 80% of Strep. pneumoniae adhesion to epithelial cells in a concentration-dependent manner. However, sera longitudinally collected from healthy children attending day care centres from 18 months of age and over the course of the following 2 years revealed: (a) development of antibodies to previously unrecognized Strep. pneumoniae surface proteins with age; (b) a quantitative increase in antibody responses, measured by densitometry, towards separated Strep. pneumoniae surface proteins with age; and (c) inhibition of Strep. pneumoniae adhesion to epithelial cells, which was 50% on average at 18 months of age, increased significantly to an average level of 80% inhibition at 42 months of age equalling adult sera inhibitory values. The results obtained in the current study, from the longitudinally collected sera from healthy children with documented repeated Strep. pneumoniae colonization, show that repeated exposures are insufficient to elicit an immune response to Strep. pneumoniae proteins at 18 months of age. This inability to recognize Strep. pneumoniae surface proteins may stem from the inefficiency of T-cell-dependent B-cell responses at this age and/or from the low immunogenicity of the proteins.