人生沒有用不到的經歷

上文在網路流傳已久，今天突然攔截到重要文句。我常以腸道免疫系統來比喻一個國家的軍隊，消化道從口腔到肛門，裡面有數不清的共生細菌，但請不要一廂情願認為共生菌真的與你共生，腸道仍有免疫系統將共生菌隔開。消化道很長，構成人體最大、最重要的免疫防線，這個免疫防線就是台灣的國軍。

http://wleemc.pixnet.net/blog/post/101772049 

共生菌對人體有益，它們會刺激腸道免疫細胞產生各種  Cytokines (如上圖 IL-4, IL-12, TNF-a, IFN-g 等)，可促進腦部發育，但共生菌對人體也會造成傷害，就像環繞台灣四週的國家，中國、日本、菲律賓、越南，請不要一廂情願認為他們真的與你共生，如果你把他們當作敵人，隨時武裝自己，台灣就會像腸道的免疫系統時常分泌 Cytokines 讓你的頭腦變得聰明。如果你認為軍人是米蟲，那你就是笨蛋，因為米蟲不會產生任何刺激你頭腦清醒的 Cytokines。

孟子說，無敵國外患者國恆亡，台灣正面臨此一問題，網路上一堆米蟲與笨蛋的論戰。

下面有一篇文章 Cytokines and CNS development (Cytokines 與中樞神經系統的發育) 發表在 Neuron，讀完英文摘要後，請愛惜自己的免疫系統--國軍，她會讓你變得聰明。該文是探討母體免疫所產生的 Cytokines 對胎兒神經細統發育的影響，另外，老鼠出生後若被放在無菌的環境中生長，會因缺少免疫系統所產生的 Cytokines，腦部發育遲緩而變得比較笨。

http://www.ncbi.nlm.nih.gov/pubmed/19840550

Cytokines are pleotrophic proteins that coordinate the host response to infection as well as mediate normal, ongoing signaling between cells of nonimmune tissues, including the nervous system. As a consequence of this dual role, cytokines induced in response to maternal infection or prenatal hypoxia can profoundly impact fetal neurodevelopment. The neurodevelopmental roles of individual cytokine signaling pathways are being elucidated through gain- and loss-of-function studies in cell culture and model organisms. We review this work with a particular emphasis on studies where cytokines, their receptors, or components of their signaling pathways have been altered in vivo. The extensive and diverse requirements for properly regulated cytokine signaling during normal nervous system development revealed by these studies sets the foundation for ongoing and future work aimed at understanding how cytokines induced normally and pathologically during critical stages of fetal development alter nervous system function and behavior later in life.