The generation of a potent humoral immune response by B cells relies on the integration of signals induced by the B cell receptor, toll-like receptors and both negative and positive co-receptors. Several reports also suggest that integrin signaling plays an important role in this process. How integrin signaling is regulated in B cells is however still partially understood. Integrin activity and function are controlled by several mechanisms including regulation by molecular adaptors of the paxillin family. In B cells, Leupaxin (Lpxn) is the most expressed member of the family and in vitro studies suggest that it could dampen BCR signaling. Here, we report that Lpxn expression is increased in germinal center B cells compared to naïve B cells. Moreover, Lpxn deficiency leads to decreased B cell differentiation into plasma cells in vitro. However, Lpxn seems dispensable for the generation of a potent B cell immune response in vivo. Altogether our results suggest that Lpxn is dispensable for T-dependent and T-independent B cell immune responses.

B 细胞产生有效的体液免疫反应依赖于 B 细胞受体、Toll 样受体以及阴性和阳性辅助受体诱导的信号整合。一些报告还表明整合素信号传导在此过程中发挥着重要作用。然而，B 细胞中整合素信号传导的调控方式仍不完全清楚。整合素活性和功能由多种机制控制，包括桩蛋白家族分子接头的调节。在 B 细胞中，Leupaxin (Lpxn) 是该家族中表达最多的成员，体外研究表明它可以抑制 BCR 信号传导。在这里，我们报告与幼稚 B 细胞相比，生发中心 B 细胞中 Lpxn 表达增加。此外，Lpxn 缺乏会导致 B 细胞在体外分化为浆细胞的能力下降。然而，Lpxn 对于体内产生有效的 B 细胞免疫反应似乎是可有可无的。总而言之，我们的结果表明 Lpxn 对于 T 依赖性和 T 独立性 B 细胞免疫反应是可有可无的。