生物谷：免疫细胞是怎样捕获和运送来自外来病原体的蛋白质的呢？研究人员在7月在线出版的《自然—免疫学》（Nature Immunology）中说，他们寻找了问题的答案。
在发动“反攻”前，免疫细胞首先需要“看到”外来抗原。但在充满免疫细胞的淋巴结中发送这样一个信号是个挑战。淋巴结是免疫系统的一个集散地，被抗体或特定的血蛋白质（也被称为补充物）所装饰的外来抗原进入淋巴结中。Jason Cyster和同事发现，一种特别的免疫细胞在淋巴结表面上捕获了这些经装饰的复合体，并将它们引导到通向抗体产生器B细胞的传送带上。然后，B细胞与外来抗原竞相发送出深藏于淋巴结中的特定抗原细胞，将它们激活，从而启动免疫系统应对入侵的外来者。
这种抗原捕获和传送的系统是如此错综复杂，通过警告侵略者的出现，它确保了免疫系统快速而有效地处理潜在的外来侵略者。（科学时报）
原始出处:
Nature Immunology
Published online: 29 July 2007 | doi:10.1038/ni1494
Subcapsular encounter and complement-dependent transport of immune complexes by lymph node B cells
Tri Giang Phan1, Irina Grigorova1, Takaharu Okada1,2 & Jason G Cyster1
Abstract
The mechanism of B cell–antigen encounter in lymphoid tissues is incompletely understood. It is also unclear how immune complexes are transported to follicular dendritic cells. Here, using real-time two-photon microscopy we noted rapid delivery of immune complexes through the lymph to macrophages in the lymph node subcapsular sinus. B cells captured immune complexes by a complement receptor–dependent mechanism from macrophage processes that penetrated the follicle and transported the complexes to follicular dendritic cells. Furthermore, cognate B cells captured antigen-containing immune complexes from macrophage processes and migrated to the T zone. Our findings identify macrophages lining the subcapsular sinus as an important site of B cell encounter with immune complexes and show that intrafollicular B cell migration facilitates the transport of immune complexes as well as encounters with cognate antigen.
Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California, San Francisco, California 94143, USA.
Present address: Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura Campus, Nishikyo-ku, Kyoto, Japan.
Correspondence to: Jason G Cyster1 e-mail: jason.cyster@ucsf.edu
