甲型流感病毒引起肺部感染会导致特定部位生发中心和 T 滤泡辅助细胞的反应。
Pulmonary infection with influenza A virus induces site-specific germinal center and T follicular helper cell responses.
机构信息
Interdisciplinary Graduate Program in Immunology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa, United States of America.
出版信息
PLoS One. 2012;7(7):e40733. doi: 10.1371/journal.pone.0040733. Epub 2012 Jul 11.
Protection from influenza A virus (IAV) challenge requires switched, high affinity Abs derived from long-lived memory B cells and plasma cells. These B cell subsets are generated in germinal centers (GCs), hallmark structures of T helper cell-driven B cell immunity. A full understanding of the GC reaction after respiratory IAV infection is lacking, as is the characterization of T follicular helper (T(FH)) cells that support GCs. Here, GC B cell and T(FH) cell responses were studied in mice following pulmonary challenge with IAV. Marked GC reactions were induced in draining lymph nodes (dLNs), lung, spleen and nasal-associated lymphoid tissue (NALT), although the magnitude and kinetics of the response was site-specific. Examination of switching within GCs demonstrated IgG2(+) cells to compose the largest fraction in dLNs, lung and spleen. IgA(+) GC B cells were infrequent in these sites, but composed a significant subset of the switched GC population in NALT. Further experiments demonstrated splenectomized mice to withstand a lethal recall challenge, suggesting the spleen to be unnecessary for long-term protection in spite of strong GC responses in this organ. Final studies showed that T(FH) cell numbers were highest in dLNs and spleen, and peaked in all sites prior to the height of the GC reaction. T(FH) cells purified from dLNs generated IL-21 and IFNγ upon activation, although CD4(+)CXCR5(-) T effector cells produced higher levels of all cytokines. Collectively, these findings reveal respiratory IAV infection to induce strong T helper cell-driven B cell responses in various organs, with each site displaying unique attributes.
针对甲型流感病毒 (IAV) 的保护需要源自长寿记忆 B 细胞和浆细胞的已成熟、高亲和力抗体。这些 B 细胞亚群是在生发中心(GC)中产生的,GC 是 T 辅助细胞驱动的 B 细胞免疫的标志性结构。人们对呼吸道 IAV 感染后的 GC 反应缺乏全面了解,也缺乏支持 GC 的滤泡辅助 T(T(FH))细胞的特征描述。在这里,研究了 IAV 肺部感染后小鼠的 GC B 细胞和 T(FH)细胞反应。尽管反应的幅度和动力学是特定部位的,但在引流淋巴结(dLNs)、肺、脾和鼻相关淋巴组织(NALT)中都诱导了明显的 GC 反应。对 GC 内的转换进行检查表明,在 dLNs、肺和脾中,IgG2(+)细胞构成最大的部分。在这些部位中,IgA(+)GC B 细胞很少,但在 NALT 的已转换 GC 群体中构成了重要的亚群。进一步的实验表明,脾切除小鼠能够承受致命的回忆性挑战,这表明尽管脾脏中存在强烈的 GC 反应,但对于长期保护来说脾脏是不必要的。最后研究表明,T(FH)细胞数量在 dLNs 和脾中最高,并在所有部位的 GC 反应达到高峰之前达到峰值。从 dLNs 中纯化的 T(FH)细胞在激活后产生 IL-21 和 IFNγ,尽管 CD4(+)CXCR5(-)T 效应细胞产生了更高水平的所有细胞因子。总的来说,这些发现揭示了呼吸道 IAV 感染会在各种器官中引发强烈的 T 辅助细胞驱动的 B 细胞反应,每个部位都具有独特的特征。