Not all passages are created equal. Part 1.
The Differentiator JangoCell Science Updates to Enlighten and Entertain Not all passages are created equal. Part 1: When to start the clock. Imagine you’re a researcher shopping for cells for your next experiment. You intend to expand these cells in culture. What do you look for when comparing cells from different commercial suppliers? We’re willing to bet that “passage number” is among your criteria to determine the best cell line for your purposes, and that you would prefer a cell line at the lowest possible passage. Luckily, your putative cell suppliers are selling all of their products at “passage 1” or “passage 2.” Depending on cell type, you might even find some products advertising “passage 0.” You must feel relieved knowing that senescence of these cells is a long way away. But wait. How can so many commercial suppliers produce so many cells at passage 1, when we know the cells would have been expanded after isolation in large enough quantities to be ready to sell? Do you know whether a “passage 1” cell line has undergone fewer population doublings than a “passage 2” cell line? Are you confident that all commercial cell suppliers even count passages in the same way? That you’re comparing apples to apples? A close examination of product descriptions for competing cell merchants makes it clear that there are some stark differences in advertised passage numbers. Many resources establish the “standard” definition of passage number and how to calculate it for cell cultures [1-3]. Such standards, however, are not sufficient to guarantee that you, the consumer, have enough information to judge different cell lines using passage number alone. For instance, there is no clear indication as to when cells should be labeled as “passage 0” when coming from primary tissues, nor how many prior population doublings
