Penttilä J M, Anttila M, Varkila K, Puolakkainen M, Sarvas M, Mäkelä P H, Rautonen N
Department of Vaccines, National Public Health Institute, Helsinki, Finland.
Immunology. 1999 Jul;97(3):490-6. doi: 10.1046/j.1365-2567.1999.00809.x.
The importance of T cells in Chlamydia pneumoniae infection in mice was assessed by comparing wild-type BALB/c mice with nude mice and mice depleted in vivo of either CD4+ or CD8+ T cells. Whereas wild-type mice cleared the primary infection in 3 weeks, nude mice were only able to restrict the infection and could not clear it during the observation period of 56 days. Nude mice exhibited a greater number of macrophages in their lungs and the pulmonary cells secreted a higher level of tumour necrosis factor-alpha (TNF-alpha) than wild-type mice. Depletion of CD4+ cells did not change the overall infection kinetics of the primary infection. However, depletion of CD8+ cells resulted in a slightly impaired clearance of the bacteria in the late stages of primary infection. To assess the role of the two T-cell subsets in the acquired immunity that develops during primary infection in wild-type BALB/c mice, in vivo depletions were performed during reinfection. Prior to reinfection, immunocompetent wild-type mice were infected and natural immunity was allowed to form. During reinfection, depletion of CD4+ cells did not have any effect on infection kinetics, whereas depletion of CD8+ cells abolished the protection, reverting the infection kinetics and bacterial load to the same levels found in wild-type mice during primary infection. These results show that T cells are necessary for clearing C. pneumoniae infection in mice. Furthermore, whereas neither of the two main T-cell subsets, separately, were essential for clearance of primary infection, the induced protective immunity was strongly CD8 dependent.
通过将野生型BALB/c小鼠与裸鼠以及体内CD4⁺或CD8⁺T细胞耗竭的小鼠进行比较，评估了T细胞在小鼠肺炎衣原体感染中的重要性。野生型小鼠在3周内清除了原发性感染，而裸鼠仅能限制感染，在56天的观察期内无法清除感染。与野生型小鼠相比，裸鼠肺部的巨噬细胞数量更多，肺细胞分泌的肿瘤坏死因子-α（TNF-α）水平更高。CD4⁺细胞的耗竭并未改变原发性感染的总体感染动力学。然而，CD8⁺细胞的耗竭导致原发性感染后期细菌清除略有受损。为了评估这两个T细胞亚群在野生型BALB/c小鼠原发性感染期间产生的获得性免疫中的作用，在再次感染期间进行了体内耗竭实验。在再次感染之前，将具有免疫能力的野生型小鼠感染，使其形成天然免疫。在再次感染期间，CD4⁺细胞的耗竭对感染动力学没有任何影响，而CD8⁺细胞的耗竭消除了保护作用，使感染动力学和细菌载量恢复到野生型小鼠原发性感染期间的相同水平。这些结果表明，T细胞对于清除小鼠肺炎衣原体感染是必需的。此外，虽然两个主要T细胞亚群单独都不是清除原发性感染所必需的，但诱导的保护性免疫强烈依赖于CD8。
