MEXi-293E cells are human embryonic kidney (HEK) cells derived from the 293 cell line and used for propagation of plasmids and expression of recombinant proteins in mammalian cells. The cell line expresses the EBNA-1 protein for episomal replication of oriP-harboring plasmids. The cell line is adapted for growth in suspension and for use with the MEXi mammalian expression system.