The microfold cells (M cells) residing in the outmost follicle-associated epithelia (FAE) of Peyer's patches capture foreign particles and hand over to sub-FAE lymphatics, where the particles are retained and disposed subsequently. A concept of “dome trap” is proposed to highlight the significance of this mechanism. For oral immunization, it is better to exploit the entrapment capacity to maximize immune response, whereas for drug delivery it is better to overcome the dome trap to transport drugs into the systemic circulation. By optimizing the size, shape, surface charges and surface properties of particles, either oral immunization or drug delivery can be potentially enhanced.

驻留在派伊尔斑块最外侧的与卵泡相关的上皮细胞（FAE）中的微褶细胞（M细胞）捕获外来颗粒，并移交给亚FAE淋巴管，这些颗粒随后被保留并处置。为了突出这种机制的重要性，提出了“圆顶陷阱”的概念。对于口服免疫，最好利用诱捕能力以最大程度地提高免疫反应，而对于药物递送，最好克服穹顶陷阱，以将药物转运到全身循环中。通过优化颗粒的大小，形状，表面电荷和表面性质，可以潜在地增强口服免疫或药物递送。