MRC5/iRFP cells are derived from he human fibroblast cell line MRC5 by stably integration of a constitutive miRFP670 stably expression construct. MRC5 cells are widely used in the studies of cell biology, virus biology, cellular aging and toxicology. MRC5/iRFP cells stably stably express miRFP670, can be used for in vitro assays and in vivo imaging.