Nowygrod R, Sutherland D E, Mauer M, Najarian J S
Transplantation. 1976 Jan;21(1):36-41.
The mammalian equivalent of the Bursa of Fabricius, the organ responsible for B cell maturation in avian species, has not been identified despite anatomic and ablative studies which suggest that the gut-associated lymphoid tissues (GALT) subserve this function. By analogy to the Bursa, the mammalian organ directing B cell ontogeny should be the site where IgM-bearing cells (B cells) are first identifiable. In this study, fluorescein-tagged heavy chain specific antirabbit IgM is used to localize initial sites of B cell appearance in rabbit fetal and neonatal lymphoid tissues. IgM-bearing cells are found 2 days before birth in the thymus and 1 day before birth in GALT. Immunoglobulin-bearing cells in spleen, lymph node, and bone marrow are undetectable until after birth. B cells bearing the IgM marked precede the appearance of IgG-bearing cells by 1 to 4 days in all instances. Intraperitoneal implantation of Millipore chambers containing immature fetal thymic tissue into neonatal hosts reveals that in situ development of IgM cells takes place independent of host cell traffic. The results suggest that B cell ontogeny in mammals is more complex than in avian species and demonstrates probable involvement of the thymus in the maturational process.
法氏囊是鸟类中负责B细胞成熟的器官，尽管解剖学和切除研究表明肠道相关淋巴组织（GALT）承担了这一功能，但哺乳动物中与之对应的器官尚未被确定。类比法氏囊，指导哺乳动物B细胞个体发育的器官应该是最早能识别出携带IgM的细胞（B细胞）的部位。在这项研究中，用荧光素标记的重链特异性抗兔IgM来定位兔胎儿和新生淋巴组织中B细胞出现的初始部位。在出生前2天于胸腺中发现了携带IgM的细胞，在出生前1天于GALT中发现。直到出生后才能检测到脾脏、淋巴结和骨髓中携带免疫球蛋白的细胞。在所有情况下，携带标记IgM的B细胞比携带IgG的细胞早出现1至4天。将含有未成熟胎儿胸腺组织的微孔室腹腔植入新生宿主，结果显示IgM细胞的原位发育独立于宿主细胞运输。结果表明，哺乳动物的B细胞个体发育比鸟类更复杂，并证明胸腺可能参与了成熟过程。
