眠り病:病原体のかくれんぼ(Sleeping sickness: pathogens play hide-and-seek)

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20024-10-30 ミュンヘン大学(LMU)

国際研究チームは、睡眠病の原因である寄生虫トリパノソーマ・ブルセイ(T. brucei)が、主に血管外組織で抗原性の表面タンパク質(VSG)を変異させ、宿主の免疫から逃れていることを発見しました。この血管外組織での抗原多様性が、寄生虫が慢性感染を維持する主な要因であり、新たな治療法の開発につながる可能性があります。

<関連情報>

組織空間はトリパノソーマ・ブルセイの抗原多様性の貯蔵庫である Tissue spaces are reservoirs of antigenic diversity for Trypanosoma brucei

Alexander K. Beaver,Zhibek Keneskhanova,Raúl O. Cosentino,Brian L. Weiss,Erick O. Awuoche,Gretchen M. Smallenberger,Gracyn Y. Buenconsejo,Nathan P. Crilly,Jaclyn E. Smith,Jill M. C. Hakim,Bailin Zhang,Bryce Bobb,Filipa Rijo-Ferreira,Luisa M. Figueiredo,Serap Aksoy,T. Nicolai Siegel & Monica R. Mugnier
Nature  Published:30 October 2024
DOI:https://doi.org/10.1038/s41586-024-08151-z

眠り病:病原体のかくれんぼ(Sleeping sickness: pathogens play hide-and-seek)

Abstract

The protozoan parasite Trypanosoma brucei evades clearance by the host immune system through antigenic variation of its dense variant surface glycoprotein (VSG) coat, periodically ‘switching’ expression of the VSG using a large genomic repertoire of VSG-encoding genes1,2,3,4,5,6. Recent studies of antigenic variation in vivo have focused near exclusively on parasites in the bloodstream6,7,8, but research has shown that many, if not most, parasites reside in the interstitial spaces of tissues9,10,11,12,13. We sought to explore the dynamics of antigenic variation in extravascular parasite populations using VSG-seq7, a high-throughput sequencing approach for profiling VSGs expressed in populations of T. brucei. Here we show that tissues, not the blood, are the primary reservoir of antigenic diversity during both needle- and tsetse bite-initiated T. brucei infections, with more than 75% of VSGs found exclusively within extravascular spaces. We found that this increased diversity is correlated with slower parasite clearance in tissue spaces. Together, these data support a model in which the slower immune response in extravascular spaces provides more time to generate the antigenic diversity needed to maintain a chronic infection. Our findings reveal the important role that extravascular spaces can have in pathogen diversification.

医療・健康
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