Animal Sciences, R.H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel.
Animal Sciences, R.H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel.
Dev Comp Immunol. 2014 May;44(1):186-94. doi: 10.1016/j.dci.2013.12.010. Epub 2013 Dec 24.
Immune protection of the gut in early life depends on provision of maternal antibodies, particularly that of IgA. In precocial birds (in this study Gallus gallus domesticus) the egg provides the only source of maternal antibodies, IgA inclusive. The gut-life of IgA in hatchlings is expected to be brief due to antigen binding and intestinal washout, and maternal IgA is likely to be depleted prior to immune independence at 7-10 days of age in the domestic fowl. We followed the track of maternal IgA in mucosal surfaces of the fowl and describe for the first time a mechanism that might provide the means to extend the active period of maternal IgA in the gut. Maternal IgA was located in the gut, lung, and cloacal bursa in embryos and hatchlings prior to the appearance of endogenic IgA positive plasma cells (D3 in the bursa or D7 in the gut and lung); the source of IgA was most probably the yolk, as the plasma was devoid of IgA till D7 post-hatch. The levels of maternal IgA decreased with time, but were still easily determined at the onset of endogenous IgA production following maturation of the adaptive immune system. Persistence of maternal IgA in the gut was enabled by goblet cell up-take by a yet un-described mechanism, and its consequent release in a mucin-like layer on enterocyte apical surfaces.
早期生命中肠道的免疫保护依赖于母体抗体的提供，特别是 IgA。在早成性鸟类（本研究中的家鸡）中，卵是提供母体抗体（包括 IgA）的唯一来源。由于抗原结合和肠冲洗，IgA 在雏鸡中的肠道寿命预计较短，并且在 7-10 日龄的家禽达到免疫独立性之前，母体 IgA 可能会耗尽。我们在家禽的黏膜表面追踪了母体 IgA，并首次描述了一种可能提供延长肠道内母体 IgA 活性期的机制。在出现内源性 IgA 阳性浆细胞（囊腔中的 D3 或肠道和肺中的 D7）之前，母体 IgA 存在于胚胎和雏鸡的肠道、肺和腔上囊中；IgA 的来源很可能是蛋黄，因为孵出后第 7 天之前，血浆中没有 IgA。母体 IgA 的水平随时间降低，但在适应性免疫系统成熟后开始产生内源性 IgA 时，仍然很容易检测到。杯状细胞通过尚未描述的机制摄取母体 IgA，并在肠上皮细胞顶端表面的粘蛋白样层中释放，从而使肠道内的母体 IgA 得以持续存在。
