Roozendaal Ramon, Carroll Michael C
Immune Disease Institute, Harvard Medical School, Boston, MA 02115, USA.
Immunol Rev. 2007 Oct;219:157-66. doi: 10.1111/j.1600-065X.2007.00556.x.
The complement system is a family of proteins that is involved in both innate and adaptive immunity. Complement receptors CD21 and CD35, which recognize activated products of C3 and C4, are predominantly expressed on B cells and follicular dendritic cells (FDCs) in the mouse. In this review, we focus on the role of FDC-expressed CD21 and CD35 in humoral immunity. They are the principle receptors for uptake and retention of immune complexes. In their absence, memory B-cell survival is markedly impaired. This is likely because of the lack of antigen but could also reflect a role for complement C3d ligand. How antigen is transported to FDCs remains an open question. In recent unpublished work using multiphoton intravital imaging, we found that small protein antigens presented in the lymph drain rapidly into B-cell follicles and are taken up by FDCs in a complement-dependent manner.
补体系统是一族参与固有免疫和适应性免疫的蛋白质。补体受体CD21和CD35可识别C3和C4的活化产物，在小鼠中主要表达于B细胞和滤泡树突状细胞（FDC）。在本综述中，我们聚焦于FDC表达的CD21和CD35在体液免疫中的作用。它们是摄取和保留免疫复合物的主要受体。在缺乏这些受体时，记忆B细胞的存活会显著受损。这可能是由于缺乏抗原，但也可能反映了补体C3d配体的作用。抗原如何转运至FDC仍是一个悬而未决的问题。在最近一项未发表的使用多光子活体成像的研究中，我们发现淋巴引流中呈现的小蛋白抗原会迅速流入B细胞滤泡，并以补体依赖的方式被FDC摄取。
