12月5日的《科學》雜志報道說，在孕婦體內(nèi),，來自母親的細胞會進入胎兒體內(nèi),，而胎兒的免疫系統(tǒng)則會學著來容忍它們，而不是像日后攻擊其它外來異物那樣對它們發(fā)動攻擊,。這種耐受性至少會持續(xù)到成年期之初,，這可解釋為什么那些需要器官移植的患者，容易對那些與他們母親的組織相類似的組織有耐受性,。
科學家很早就知道,，發(fā)育中的胎兒免疫系統(tǒng)會對異物具有不同尋常的耐受性,。可是,，除此之外,，人們對有關人類胎兒免疫系統(tǒng)卻所知甚少。一些研究是在小鼠上進行的,，但小鼠與人類免疫系統(tǒng)的發(fā)育速度不同,，因此在子宮中對外來物質(zhì)的反應也有很大差異。
加州大學舊金山分校Jeff Mold及同事報告說,，他們通過研究人類組織發(fā)現(xiàn),，有令人驚詫的大量的孕婦細胞會進入胎兒的淋巴結。這些細胞在那里會誘導一群調(diào)節(jié)性的T細胞來抑制胎兒對母體細胞的免疫反應,。與小鼠的免疫系統(tǒng)相反,，人類胚胎的T細胞看來在受到母體抗原的刺激時非常容易成為調(diào)節(jié)性的T細胞。研究人員表示,，在出生之后,，這些調(diào)節(jié)性的T細胞會繼續(xù)抑制針對母體細胞的免疫反應。 （生物谷Bioon.com）
生物谷推薦原始出處：
Science,，Vol. 322. no. 5907, pp. 1562 - 1565,，Jeff E. Mold，Joseph M. McCune
Maternal Alloantigens Promote the Development of Tolerogenic Fetal Regulatory T Cells in Utero
Jeff E. Mold,1,2 Jakob Micha?lsson,3 Trevor D. Burt,1,4 Marcus O. Muench,5 Karen P. Beckerman,6* Michael P. Busch,5 Tzong-Hae Lee,5 Douglas F. Nixon,1 Joseph M. McCune1
As the immune system develops, T cells are selected or regulated to become tolerant of self antigens and reactive against foreign antigens. In mice, the induction of such tolerance is thought to be attributable to the deletion of self-reactive cells. Here, we show that the human fetal immune system takes advantage of an additional mechanism: the generation of regulatory T cells (Tregs) that suppress fetal immune responses. We find that substantial numbers of maternal cells cross the placenta to reside in fetal lymph nodes, inducing the development of CD4+CD25highFoxP3+Tregs that suppress fetal antimaternal immunity and persist at least until early adulthood. These findings reveal a formof antigen-specific tolerance in humans, induced in utero and probably active in regulating immune responses after birth.
1 Division of Experimental Medicine, Department of Medicine, University of California at San Francisco (UCSF), San Francisco, CA 94110, USA.
2 Biomedical Sciences Graduate Program, UCSF, San Francisco, CA 94143, USA.
3 Center for Infectious Medicine, Department of Medicine, Karolinska University Hospital, Karolinska Institutet, 141 86, Stockholm, Sweden.
4 Department of Pediatrics, Division of Neonatology, UCSF, San Francisco, CA 94143, USA.
5 Blood Systems Research Institute and Department of Laboratory Medicine, UCSF, San Francisco, CA 94118, USA.
6 Department of Obstetrics, Gynecology, and Reproductive Sciences, UCSF, San Francisco, CA 94143, USA.
