Tonsil-derived mesenchymal progenitor cells acquire a follicular dendritic cell phenotype under cytokine stimulation.

Tonsils comprise part of the mucosal immune system and contain lymphocytes, macrophages, and follicular dendritic cells (FDCs). FDCs are located in the B cell area of the follicles of secondary lymphoid organs, such as the spleen, tonsils, or lymph nodes, and they trap and retain immune complexes on their surfaces to regulate B cell activation and maturation. Stromal cells from the palatine tonsils are often used for FDC in vitro studies, and it has been reported that human palatine tonsils may be a good source of multipotent mesenchymal cells. Therefore, we assessed whether tonsil-derived mesenchymal stromal cells could differentiate into a FDC-like phenotype. We discovered that stromal cells isolated from human tonsils not only had the potential to differentiate into various cell types of mesenchymal origin, but they also could differentiate into FDC-like cells under cytokine stimulation in vitro.