B cells serve as the primary producers of antibodies within the immune system. To elicit an effective immune response, they must recognize and internalize antigens through a specialized signaling platform known as the immune synapse. The formation of this structure involves the generation of forces and the polarization of cellular structures. In our research, we employ microfluidics and micro-fabricated tools to investigate the forces present at cell-cell contacts and the cellular rearrangements triggered by antigen recognition. Recently, we introduced functionalized oil droplets as a novel antigen presenting tool, revealing an unexpected role for microtubules in limiting F-actin polymerization, thus facilitating the formation and maintenance of a distinct immune synapse. Furthermore, I will present novel applications of these methods, focusing on exploring the interaction of B cells with the micro-environment of lymph nodes and assessing the impact of mechanical factors on their immune function.