Commercial cell-based tissue-engineered products

The majority of the cell-based assays use established cell lines. The cell line of choice would naturally express receptors of interest that respond to the therapeutic protein product, and can be obtained from commercial sources, American Type Culture Collection (ATCC), for example. Alternatively, if an appropriate commercially sourced cell line cannot be found, one can be engineered to respond to a therapeutic protein (see b.Reporter Gene Assay). Most frequently the cells are stably transfected with a vector containing the desired receptor gene or responsive element of a gene of interest. In rare instances when the cell lines are not available, primary cells separated from blood or tissues (human or animal) can be used to develop bioassays. Primary cells are the last resort because of donor-to-donor variability, accessibility of material, and limited practicality of such assays. 

---