東亞家蝠氣管與腸道類器官模型之建立與禽流感病毒感染潛力之探討

Abstract

蝙蝠是許多新興傳染病與人畜共通疾病的重要保毒宿主，其與病毒之間的交互關係極具研究價值。蝙蝠已被發現可作為流感病毒（如H17、H18及H9亞型）的自然宿主；然而，由於H17與H18型病毒迄今尚未成功分離，且蝙蝠的研究模型相對缺乏，加上不同蝙蝠的物種差異性甚大，對病毒的感受性也存在差異，限制了蝙蝠與流感病毒研究的深入發展。本研究旨在建立臺灣常見蝙蝠東亞家蝠與東亞摺翅蝠之三維細胞培養模型，包括氣管與腸道類器官，以及氣管氣液介面（air-liquid interface, ALI）系統，以作為研究蝙蝠流感病毒的實驗平台；且運用反轉錄偽病毒研究H17與H9病毒進入宿主細胞的能力，進一步探討其感染潛力；同時使用與蝙蝠H9N2病毒序列高度相似之禽類H9N2病毒進行感染實驗，最後嘗試以反轉基因法生成蝙蝠H9N2病毒。本研究成功建立蝙蝠氣管與腸道的3D類器官及ALI系統；在偽病毒實驗中發現多數哺乳類細胞株對蝙蝠H9的感受性高於H17，且溫度提升或轉染CIITA都並未顯著增強感染能力。進一步以蝙蝠3D模型進行感染試驗，發現東亞家蝠之氣管類器官對H9N2禽流感病毒具明顯感受性，反之H9N2禽流感病毒無法在東亞家蝠腸道類器官複製；利用不同型態的類器官模擬病毒的傳播方式，根據結果推估H9N2禽流感病毒可能具備由蝙蝠呼吸道侵入、感染呼吸道上皮、進而藉呼吸道傳播之潛力。本研究成功建立臺灣常見蝙蝠東亞家蝠與東亞摺翅蝠之三維細胞培養系統，結合偽病毒與禽流感病毒實驗，初步揭示臺灣蝙蝠對H9N2流感病毒之感受性與傳播潛力，未來的研究將致力於產生蝙蝠來源H9N2病毒，利用本研究建立之模型，進一步探索蝙蝠作為流感病毒潛在宿主的可能性，以及其對病毒演化的影響。

Bats are important reservoir hosts for many emerging and zoonotic diseases, and their interactions with viruses are worthwhile for study. Bats have been identified as natural hosts for influenza virus subtypes, such as H17, H18, and H9. However, the study of bat-influenza virus interaction remains limited due to the inability to isolate H17 and H18 viruses, and the lack of a suitable bat-specific model. This study aimed to establish three-dimensional (3D) cell culture models, including tracheal and intestinal organoids, as well as air-liquid interface (ALI) tracheal systems, from two common bat species in Taiwan: Pipistrellus abramus (P. abramus) and Miniopterus fuliginosus (M. fuliginosus). These models served as experimental platforms for studying bat influenza viruses. We employed a retroviral pseudotyped system to investigate H17 and H9 entry. In addition, we used an avian H9N2 virus with high sequence similarity to bat-derived H9N2 to perform infection experiments, and we attempted to rescue the bat H9N2 virus using reverse genetics techniques. In the result, we successfully established 3D tracheal and intestinal organoids and ALI systems from bat tissues. In the pseudovirus experiments, most mammalian cell lines exhibited higher susceptibility to bat H9 than to H17. Moreover, neither elevated temperatures nor CIITA-transfected cells enhanced infection efficiency. In avian H9N2 infection assays using the 3D bat models, P. abramus tracheal organoids showed clear susceptibility, while the intestinal organoids did not. This study successfully established a 3D cell culture platform using two common Taiwanese bat species, providing a feasible model for studying bat–influenza virus interactions. The use of pseudotyped viruses offers a safer approach to studying bat influenza virus entry, while the infection experiments in bat 3D organoids provide insights into the susceptibility of bats to avian influenza viruses, especially for P. abramus and M. fuliginosus. In the future, we aim to successfully rescue the bat-derived H9N2 virus and continue using this platform to explore the potential of bats as influenza virus hosts and their role in viral evolution.