人們一直認(rèn)為,，就像走路和說話一樣，當(dāng)嬰兒長大時(shí),，他們也逐漸產(chǎn)生抵抗病毒感染的能力,。但是來自美國密歇根大學(xué)健康系統(tǒng)的研究人員提出，嬰兒對(duì)抗感染的自然能力在早期就已經(jīng)產(chǎn)生了,。
科學(xué)家們了解到在生命初期,，關(guān)鍵性細(xì)胞信號(hào)抑制至關(guān)重要的免疫細(xì)胞產(chǎn)生。根據(jù)一篇提前發(fā)表在Nature Immunology期刊上的一篇研究論文,，阻斷這種信號(hào)能夠提高嬰兒抵抗感染的能力,。在嬰兒年幼時(shí)，自然殺傷細(xì)胞(natural killer cell)像很多其他免疫細(xì)胞一樣,，直到他們進(jìn)入成年時(shí)才能夠完成成熟并充分發(fā)揮出它們的功能,。在這期間，嬰兒的免疫系統(tǒng)是不成熟的,，而不能保護(hù)他們抵抗感染,，這也是為什么新生兒和嬰兒更容易被感染的原因。
在這項(xiàng)研究中，密歇根大學(xué)研究人員證實(shí)轉(zhuǎn)化生長因子-β(transforming growth factor beta, TGF-β)所起的作用能夠解釋其中的原因,。在研究中,，他們發(fā)現(xiàn)自然殺傷細(xì)胞的產(chǎn)生是受TGF-β控制著的，其中TGF-β在骨髓中產(chǎn)生,。在幼鼠中,，當(dāng)TGF-β信號(hào)缺失時(shí)，自然殺傷細(xì)胞的成熟更加快速地進(jìn)行,。到成年時(shí),，如果TGF-β信號(hào)被阻斷的話，小鼠擁有的自然殺傷細(xì)胞數(shù)量增加了10多倍,。而且當(dāng)TGF-β信號(hào)被阻斷時(shí),，自然殺傷細(xì)胞在小鼠出生10天后就能夠完成成熟。(生物谷：Bioon.com)
本文編譯自Why do infants get sick so often? Researchers reveal cell signaling prevents growth of essential immune cells
doi: 10.1038/ni.2388
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TGF-β is responsible for NK cell immaturity during ontogeny and increased susceptibility to infection during mouse infancy
Jeffrey P Marcoe, James R Lim, Keri L Schaubert, Nassima Fodil-Cornu, Marsel Matka, Alexandra L McCubbrey, Alexander R Farr, Silvia M Vidal & Yasmina Laouar
A large gap in our understanding of infant immunity is why natural killer (NK) cell responses are deficient, which makes infants more prone to viral infection. Here we demonstrate that transforming growth factor-β (TGF-β) was responsible for NK cell immaturity during infancy. We found more fully mature NK cells in CD11cdnR mice, whose NK cells lack TGF-β receptor (TGF-βR) signaling. Ontogenic maturation of NK cells progressed faster in the absence of TGF-β signaling, which results in the formation of a mature NK cell pool early in life. As a consequence, infant CD11cdnR mice efficiently controlled viral infections. These data thus demonstrate an unprecedented role for TGF-β in ontogeny that can explain why NK cell responses are deficient early in life.
