2. Often to do experimental analyses on immune cells, we need to “culture” them, or keep them alive for days or weeks. It is very challenging to culture 1 ̊ (primary) leukocyte because they don’t survive well outside the body, and are also programmed to die after a short life, instead of proliferate. Often scientists use cultured immortalized “cell lines” as an alternative to 1 ̊ cells. These kinds of cells have alterations such as mutations or viral infections that allow them to grow in flasks, but still retain many of the characteristic of the cell type they were obtained from. The ATCC (American Type Culture Collection) is a repository of many of these cell types. Look up HeLa cells and RAW-267.7 cells at the ATCC, and write down what type of cells they are (species, cell type). Which would be more appropriate for studies of immune cell function? What type of immune cell?