Sinha Rajesh K, Mage Rose G
Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institute of Heath, Building 10, Room 11N311, 10 Center Drive, MSC 1892, Bethesda, MD 20892, USA.
Dev Comp Immunol. 2004 Jun;28(7-8):829-41. doi: 10.1016/j.dci.2004.01.003.
Young rabbit appendix is a homologue of chicken bursa of Fabricius; both are crucial sites for preimmune B-cell repertoire development. We describe here some of the molecules involved in the multi-step recruitment of blood-borne B cells into neonatal rabbit developing appendix. Sialyl-Lewis-x, CD62L and integrins such as LFA-1 and alpha4beta1 were detected on B cells in peripheral blood. Peripheral lymph node addressin (PNAd), a CD62L counter-receptor was observed on appendix HEV. We also detected chemokine receptor CCR7 on peripheral blood B cells and one of the CCR7 ligands, CCL21, on appendix HEV but not in appendix follicles. Higher levels of CXCR5 expression compared to CCR7 on appendix B cells suggest that CXCR5 may be involved in recruitment of B cells into follicles. The proportions of appendix B cells expressing CD62L, sialyl-Lewis-x and alpha4beta1 declined between day 3 and 4 weeks after birth while percentages of Lewis-x+ appendix B cells increased. These changes correlate with the stage of repertoire diversification by gene conversion in both rabbits and chickens. The cross-reactivity of antibodies to mouse or human adhesion molecules described in this study indicates that some of the structures of these important molecules are conserved across species.
幼兔阑尾是鸡法氏囊的同源物；二者都是免疫前B细胞库发育的关键部位。我们在此描述了参与血源性B细胞多步骤募集至新生兔发育中的阑尾的一些分子。在外周血B细胞上检测到唾液酸化路易斯-x、CD62L以及诸如淋巴细胞功能相关抗原-1（LFA-1）和α4β1等整合素。在阑尾高内皮微静脉（HEV）上观察到外周淋巴结地址素（PNAd），它是CD62L的反受体。我们还在外周血B细胞上检测到趋化因子受体CCR7，在阑尾HEV上检测到CCR7配体之一CCL21，但在阑尾滤泡中未检测到。与阑尾B细胞上的CCR7相比，CXCR5表达水平更高，这表明CXCR5可能参与B细胞募集至滤泡。出生后第3天至第4周，表达CD62L、唾液酸化路易斯-x和α4β1的阑尾B细胞比例下降，而路易斯-x+阑尾B细胞百分比增加。这些变化与兔和鸡通过基因转换实现的库多样化阶段相关。本研究中描述的针对小鼠或人黏附分子的抗体的交叉反应性表明，这些重要分子的一些结构在物种间是保守的。
