インフルエンザ感染応答における抗体産生細胞の新機能を解明(Antibody-making cells reveal new function in response to flu infection)

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2025-09-03 ペンシルベニア州立大学(PennState)

ペンシルベニア州立大学の研究で、抗体を産生するB細胞がインフルエンザ感染時に新たな役割を果たすことが判明した。従来、炎症性サイトカインIL-1βはマクロファージなど自然免疫細胞が作ると考えられていたが、今回リンパ節内の胚中心(GC)B細胞がNLRP3インフラマソームを介してIL-1βを産生し、T濾胞性ヘルパー細胞(TFH)の働きを支え、GC維持と抗体応答の強化に寄与することが明らかになった。インフラマソームやIL-1βが欠損するとTFH機能やGC形成が不十分になり、免疫応答が弱まる。B細胞は単なる抗体工場ではなく免疫調節因子でもあることが示され、インフルエンザワクチンの改良やがん・自己免疫疾患への新規治療法開発に道を開く成果となった。研究結果は『PLOS Pathogens』に掲載された。

<関連情報>

インフルエンザ感染後、胚中心B細胞は正統的NLRP3炎症小体活性を介してTFH細胞に必須のIL-1βシグナルを提供する Germinal Center B cells provide essential IL-1β signals to TFH cells via canonical NLRP3 inflammasome activity post influenza infection

Juliana Restrepo Munera,Cainan Riccio-Baum,Rebecca Kaddis Maldonado,S. Rameeza Allie
PLOS Pathogens  Published: August 18, 2025
DOI:https://doi.org/10.1371/journal.ppat.1013404

インフルエンザ感染応答における抗体産生細胞の新機能を解明(Antibody-making cells reveal new function in response to flu infection)

Abstract

Persistent germinal center (GC) responses show increased benefit in optimal responses to influenza infection. Follicular helper T (TFH) cells provide the essential signals and help for maintenance of GCs and require IL-1β signaling for establishment and maintenance. We observe a preferential upregulation of IL-1β within GC B cells and coexpression of NLRP3 and caspase-1 with IL-1β confirms that GC B cells process IL-1β using a canonical NLRP3/caspase-1 mechanism. Using B cell specific ablation of IL-1β production and IL-1β signaling we further confirm that, GC B cells are the primary source of vital IL-1β within the GC and that IL-1β processing by GC B cells post influenza infection is driven by NLRP3 inflammasomes. We observe significant reduction of GC B cells and TFH cells in the absence of B cell derived IL-1β and our analysis of human B cells suggests similar mechanisms in human GC B cells. Our data present GC B cells in two novel roles, the first in producing IL-1β, which is associated with innate functions, within the GC and the second is providing helper cytokine to the TFH cell. Our findings add to the known complexity of the GC providing a target to enhance GC function and persistence.

Author summary

Follicular helper T (TFH) cells require IL-1B to optimally function within the germinal center (GC). We identify GC B cells as a previously unrecognized source of IL-1β, within the GC microenvironment and demonstrate that B cell–derived IL-1β is necessary for TFH and GC function, including follicular trafficking, even when all other cells retain IL-1β production capacity. We delineate the inflammasome pathway responsible for IL-1β expression in GC B cells and validate these findings in the context of influenza infection and show that analogous pathways operate in the human system, highlighting the broader relevance of B cell–derived IL-1β in shaping adaptive immunity.

 

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