Intestinal immunity is triggered mainly by M cells existing in the intestinal tract by uptake antigens to gut associated lymphoid tissue (GALT). Recently, it has been attracting attention as a target of oral vaccine. However, primary culture is difficult because the number of M cells in vivo is small. Therefore, an in vitro human M cell model that can evaluate vaccines targeting M cells is required. If an in vitro human M cell model is constructed, we thought that we could contribute to the development of targeted oral vaccines and basic research on the function of human M cells. We constructed an in vitro human M cell model and evaluated the uptake of bacteria using cultured cells. M cell model was constructed by using the co-cultured of C2BBe1 and Raji cells, in which C2BBe1 was cultivated on the cell insert membrane and Raji cells in the well. We attempted to construct a new model by adding GST-RANKL, in which GST tag attached to RANKL(receptor activator of NF-κB ligand), a protein involved in differentiation into M cells. After co-culture, the number of fluorescent beads that was uptake by M cell (a functional evaluation), and the expression level of the M cell marker sialyl Lewis A antigen were compared with the co-culture model. In both evaluations, the new model showed improvement compared to the co-culture model.
