Following immunization, lymph nodes dynamically expand and contract. The mechanical and cellular changes enabling the early-stage expansion of lymph nodes have been characterized, yet the durability of such responses and their implications for adaptive immunity and vaccine efficacy are unknown. Here, by leveraging high-frequency ultrasound imaging of the lymph nodes of mice, we report more potent and persistent lymph-node expansion for animals immunized with a mesoporous silica vaccine incorporating a model antigen than for animals given bolus immunization or standard vaccine formulations such as alum, and that durable and robust lymph-node expansion was associated with vaccine efficacy and adaptive immunity for 100 days post-vaccination in a mouse model of melanoma. Immunization altered the mechanical and extracellular-matrix properties of the lymph nodes, drove antigen-dependent proliferation of immune and stromal cells, and altered the transcriptional features of dendritic cells and inflammatory monocytes. Strategies that robustly maintain lymph-node expansion may result in enhanced vaccination outcomes.

免疫后，淋巴结动态扩张和收缩。使淋巴结早期扩张的机械和细胞变化已经被表征，但这种反应的持久性及其对适应性免疫和疫苗功效的影响尚不清楚。在这里，通过利用小鼠淋巴结的高频超声成像，我们报告说，与接受推注免疫或标准疫苗制剂（例如，明矾，并且在黑色素瘤小鼠模型中，持久而强劲的淋巴结扩张与疫苗功效和接种后 100 天的适应性免疫有关。免疫改变了淋巴结的机械和细胞外基质特性，驱动了免疫细胞和基质细胞的抗原依赖性增殖，并改变了树突状细胞和炎性单核细胞的转录特征。强有力地维持淋巴结扩张的策略可能会提高疫苗接种效果。