先天免疫系統是一個古老且高度保留的免疫抵禦機制，其提供抵禦病原菌的第一道防線。因為線蟲並沒有後天免疫 (adapted immunity)系統，所以提供了一個很好的平台去研究先天免疫，也可讓我們研究特定基因如何參與病原菌的抵禦機制。根據先前的研究，先天免疫會被病毒或是細菌之病原相關分子標誌(PAMPs)以及非病原菌因子之損害相關分子標誌(DAMPs)所活化。不管是病原相關分子標誌還是非病原菌因子，DNA都是一種可以活化先天免疫反應的常見物質。然而，對於DNA如何被細胞偵測並且參與先天免疫系統的活化的了解還是很少。這裡我們發現一個線蟲之DNase II似乎扮演了調控先天免疫的角色。我們初步的結果顯示，在線蟲中跟人類DNase II-alpha的同源基因為crn-7，且其突變株對於病原菌有較高的抵抗能力。我們也發現crn-7的突變株有較高的先天免疫能力而且可能跟細胞質核酸感應系統有關。總結而言，在這邊我們提供了一個很好的活體動物模式去研究胞質核酸感應系統如何被病原相關分子標誌及損害相關分子標誌所活化。

Innate immune system is an ancient and evolutionarily conserved defense mechanism and provides the first line of defense against pathogens. C. elegans provides powerful platforms for studying the function of innate immunity and a specific gene to protect the host from infection. According to previous studies, innate immunity is stimulated not only by viral or bacterial components (pathogen-associated molecular patterns, PAMPs), but also by non-microbial danger signals (damage-associated molecular patterns, DAMPs). However, the knowledge of how the cytosolic DNA, a potential PAMP or DAMP, can be sensed is still limited. Here, we showed a DNase II play an important role in the regulation of innate immunity in C. elegans. Our preliminary results indicated that the deficiency of a DNase II, Crn-7, in C. elegans enhances the innate immune responses against several bacterial pathogens. Furthermore, the cytosolic nucleic acid sensing system could be, partlly, the downstream signal of this enhanced immune response. In sum, we have established an in vivo model for studying the pathogen- or damage-associated cytosolic DNA recognition.

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