A line of products for cell immortalization enables researchers to use the same consistent materials throughout a research project without having to establish new cultures. Both immortalized cell lines and the tools for immortalizing cells are available. The products utilize telomerase reverse transcriptase (TERT) technology from Geron Corp. The two TERT-immortalized cell lines available are the human retinal pigmented epithelium cells and human foreskin fibroblasts. A eukaryotic expression plasmid containing the hTERT cDNA clone, which researchers can use to immortalize their own cells, is also available. The product line will expand as more hTERT-immortalized cell lines are developed. Products are subject to a limited licensing agreement and the hTERT clone is distributed to not-for-profit institutions only. Immortalized cell lines can replicate in culture for an extended period of time. Expression of the hTERT protein immortalizes cells while maintaining the characteristics of source tissue.