嬰兒早期腸道中如果繁殖有大量的大腸桿菌，則嬰兒機體的血液中將會有較多數(shù)量的記憶B細胞,，近日,，來自瑞典歌德堡大學的研究者這樣表示。相關研究成果刊登在了國際雜志The Journal of Immunology上,。
我們腸道中的細菌遠遠超過我們機體中的細胞數(shù)量,，而且這些細菌對于機體的健康至關重要，因為細菌可以刺激人類機體的免疫系統(tǒng)成熟。一般情況下,，正常的腸道細菌菌群是在我們人類生命初期開始建立的,，但是近年來人類增加的衛(wèi)生生活方式改變了細菌菌群。
目前來講,，大腸桿菌在瑞典的兒童的腸道中寄居時間越來越晚,，而且在腸道中開始存在少量各種各樣的不同的細菌，于此同時,，因為免疫調節(jié)缺失所引起的疾病不斷增加,，使得變態(tài)反應成為西方國家一個主要的公眾健康問題。
B細胞在變態(tài)反應發(fā)展的過程中扮演者重要角色
B細胞是一種白細胞,，可以通過產生抗體來保護機體免受感染以及在變態(tài)反應的發(fā)展過程中起到了關鍵的作用,。研究者們通過對B細胞進行相關研究，以及Vastra Gotaland地區(qū)65個健康新生兒的相關研究,，表明在出生一周的嬰兒腸道內如果有大腸桿菌寄居的話,，在嬰兒成長至4個月和18個月的時候，其體內的記憶B細胞數(shù)量會大量增加,。這樣的結果對于我們理解腸道細菌菌群和免疫系統(tǒng)發(fā)展之間的關系至關重要,，而且提醒我們過度衛(wèi)生生活方式多帶來的健康風險。
研究者表示,，人類周圍的的大部分細菌都是無害的,，我們應該視它們?yōu)殄憻捨覀儥C體免疫力的一種鍛煉方式，一遍我們的免疫系統(tǒng)可以成熟地更加完全,，健康的新生兒并不需要過度保護而使其不與細菌接觸,。（生物谷：T.Shen<微博>編譯）
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doi:10.4049/jimmunol.1103223
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Infant B Cell Memory Differentiation and Early Gut Bacterial Colonization
Anna-Carin Lundell*, Viktor Björnsson*, Annika Ljung†, Margareta Ceder‡, Susanne Johansen§, Gunhild Lindhagen¶, Carl-Johan Törnhage‖, Ingegerd Adlerberth†, Agnes E. Wold† and Anna Rudin*
Germ-free animal models have demonstrated that commensal bacterial colonization of the intestine induces B cell differentiation and activation. Whether colonization with particular bacterial species or groups is associated with B cell development during early childhood is not known. In a prospective newborn/infant cohort including 65 Swedish children, we examined the numbers and proportions of CD20+, CD5+, and CD27+ B cells in blood samples obtained at several time points during the first 3 y of life using flow cytometry. Fecal samples were collected and cultured quantitatively for major facultative and anaerobic bacteria at 1, 2, 4, and 8 wk of life. We found that the numbers of CD20+ B cells and CD5+CD20+ B cells reached their highest levels at 4 mo, whereas CD20+ B cells expressing the memory marker CD27 were most numerous at 18 and 36 mo of age. Using multivariate analysis, we show that early colonization with Escherichia coli and bifidobacteria were associated with higher numbers of CD20+ B cells that expressed the memory marker CD27 at 4 and 18 mo of age. In contrast, we were unable to demonstrate any relation between bacterial colonization pattern and numbers of CD20+ or CD5+CD20+ B cells. These results suggest that the intestinal bacterial colonization pattern may affect the B cell maturation also in humans, and that an early gut microbiota including E. coli and bifidobacteria might promote this maturation.
