Rickert R C, Rajewsky K, Roes J
Institute for Genetics, University of Cologne, Germany.
Nature. 1995 Jul 27;376(6538):352-5. doi: 10.1038/376352a0.
CD19 is the hallmark differentiation antigen of the B lineage. Its early expression has implicated a role for CD19 during the antigen-independent phases of B-cell development, whereas in mature B cells CD19 can act synergistically with surface immunoglobulin to induce activation. We have generated CD19-deficient mice and found that development of conventional B cells is unperturbed. However, mature CD19-/- B cells show a profound deficiency in responding to protein antigens that require T-cell help. This is accompanied by a lack of germinal centre formation and affinity maturation of serum antibodies. Thus CD19 is crucial for both initial B-cell activation by T-cell-dependent antigens and the maturation and/or selection of the activated cells into the memory compartment. An impairment in ligand-driven selection may also be responsible for the observation of a striking reduction in the B-1 (formerly Ly-1) B-cell subset, thought to develop under the control of self-antigens and bacterial antigens (reviewed in ref. 2).
CD19是B淋巴细胞系的标志性分化抗原。其早期表达表明CD19在B细胞发育的抗原非依赖阶段发挥作用，而在成熟B细胞中，CD19可与表面免疫球蛋白协同作用诱导激活。我们构建了CD19缺陷小鼠，发现传统B细胞的发育未受干扰。然而，成熟的CD19基因敲除B细胞在对需要T细胞辅助的蛋白质抗原作出反应方面存在严重缺陷。这伴随着生发中心形成的缺乏和血清抗体的亲和力成熟。因此，CD19对于T细胞依赖性抗原引发的初始B细胞激活以及激活细胞向记忆库的成熟和/或选择都至关重要。配体驱动的选择受损也可能是观察到B-1（以前称为Ly-1）B细胞亚群显著减少的原因，该亚群被认为是在自身抗原和细菌抗原的控制下发育的（参考文献2中有综述）。
