流感疫苗接種後生發中心參與記憶和初始B細胞形成
作者:
小柯機器人發布時間:2020/9/2 16:05:30
美國華盛頓大學醫學院Ali H. Ellebedy研究組發現,人接種流感疫苗後, 生發中心(GC)參與記憶和初始B細胞形成。 2020年8月31日,《自然》在線發表了這一成果。
使用超聲引導細針抽吸對引流淋巴結(LN)連續採樣,研究人員探究了人接種流感疫苗後GC B細胞反應的動力學和特異性。研究人員發現在疫苗接種1周內可檢測到結合流感疫苗的GC B細胞。有八分之三的參與者在疫苗接種9周後仍可以檢測到結合疫苗的GC B細胞。應答GC B細胞克隆中有12%至88%與早期循環漿母細胞中檢測到的克隆重疊。這些共享的B細胞克隆具有高頻的體細胞超突變(SHM),並編碼廣泛的交叉反應性單克隆抗體(mAb)。
相比之下,僅在GC內檢測到的疫苗誘導的B細胞克隆具有明顯較低的SHM頻率,並且主要編碼菌株特異性mAb,表明它來源於原始B細胞。電子顯微鏡表位作圖顯示,這些菌株特異性mAb可識別某些早期成漿細胞非靶向的表位。
該研究結果表明,人接種流感病毒疫苗可引發GC反應,更有可能招募針對新型抗原決定簇的B細胞克隆,從而擴大了疫苗誘導的針對快速變異病原體保護性抗體的範圍。
據了解,流感仍然是產生公共衛生威脅的原因之一。季節性流感疫苗接種主要會刺激先前存在的記憶B細胞,從而導致循環系統中分泌抗體的成漿細胞短暫生成。這種召喚反應導致「原始抗原罪」,即先前暴露於流感病毒抗原的抗體特異性選擇性增強。尚不清楚這種疫苗是否還能在引流LN中誘發生發中心反應,多樣和成熟B細胞被招募至引流淋巴結。
附:英文原文
Title: Human germinal centres engage memory and naive B cells after influenza vaccination
Author: Jackson S. Turner, Julian Q. Zhou, Julianna Han, Aaron J. Schmitz, Amena A. Rizk, Wafaa B. Alsoussi, Tingting Lei, Mostafa Amor, Katherine M. McIntire, Philip Meade, Shirin Strohmeier, Rafael I. Brent, Sara T. Richey, Alem Haile, Yuhe R. Yang, Michael K. Klebert, Teresa Suessen, Sharlene Teefey, Rachel M. Presti, Florian Krammer, Steven H. Kleinstein, Andrew B. Ward, Ali H. Ellebedy
Issue&Volume: 2020-08-31
Abstract: Influenza viruses remain a major public health threat. Seasonal influenza vaccination in humans primarily stimulates pre-existing memory B cells, leading to a transient wave of circulating antibody-secreting plasmablasts1–3. This recall response contributes to 「original antigenic sin,」 the selective boosting of antibody specificities from prior exposures to influenza virus antigens4. It remains unclear whether such vaccination can also induce germinal centre (GC) reactions in the draining lymph node (LN) where diversification and maturation of recruited B cells can occur5. Here we used ultrasound-guided fine needle aspiration to serially sample the draining LNs and investigate the dynamics and specificity of GC B cell responses after influenza vaccination in humans. We show that influenza vaccine-binding GC B cells can be detected as early as 1 week after vaccination. In 3 out of 8 participants, we detected vaccine-binding GC B cells up to 9 weeks after vaccination. Between 12% and 88% of the responding GC B cell clones overlapped with those detected among early circulating plasmablasts. These shared B cell clones had high frequencies of somatic hypermutation (SHM) and encoded broadly cross-reactive monoclonal antibodies (mAbs). In contrast, vaccine-induced B cell clones detected only in the GC compartment exhibited significantly lower SHM frequencies and predominantly encoded strain-specific mAbs, suggesting a naive B cell origin. Electron microscopy-based epitope mapping revealed that some of these strain-specific mAbs recognized epitopes that were not targeted by the early plasmablast response. Our results indicate that influenza virus vaccination of humans can elicit a GC reaction to which B cell clones targeting novel epitopes are more likely to be recruited, thereby broadening the spectrum of vaccine-induced protective antibodies against this rapidly mutating pathogen.
DOI: 10.1038/s41586-020-2711-0
Source: https://www.nature.com/articles/s41586-020-2711-0