A secondary cultured cell population that represents a genetically stable and homogenous population of cultured cells that shares a common propagation history (ie has been successively passaged together in culture). 1. The term 'line' is used when a culture has undergone an intentional experimental process to establish a more uniform and stable population of cells (see 'establishing cell line'). This will require one or more passages, but may involve additional selection processes. Through such passaging and/or selection processes, the resulting 'line' attains some level of genetic stability and compositional homogeneity which is typically absent in primary cultures. Because of their relative homogeneity, 'lines' are capable of being characterized and stably propagated over a period of time. A *new* cell line can be "established" not only through the passaging/selection of a primary culture, but also through experimental modifications of existing lines (e.g. immortalization, stable genetic modifications, drug selection for a resistant subset, etc.). As defined here, 'cell line' can refer to a population of cells in active culture, applied experimentally, or stored in a quescent state for future use. 2. The definitional criteria provided here for the 'cell line' class demarcates populations that represent what researchers actually use in the practice of science - e.g. as inputs to culturing, experimentation, and sharing. The definition is such that cell lines will exhibit important attributes. For example, they will have a relatively homogenous cell type composition as they have experienced similar selective pressures due to their continuous co-propagation. In addition, these populations can also be characterized by a passage number, again owing to their common passaging history.? 3. Definitinal criteria are intended to be sufficiently clear to specify what are and what are not instances of 'cell lines' in the real world. A 'HeLa cell line' would be a subset of all HeLa cells in the world - specifically any subset that has been derived through a shared continuous lineage wherein the cells have always been passaged together and thereby evolved together through the selective pressures imposed by this common history. Accordingly, 'HeLa cell line' would not be used to refer to the collection of all HeLa cells in a given lab, or all HeLa cells in the ATCC repository, as cells in these collections will likely not all share a common culture history. Rather, 'HeLa cell line' could refer to the collection of cells I am culturing at a given moment, or that I apply in an experiment (as such collections typically meet the criteria of having a shared propagation history). As noted above, it is such collections that are typically referred to in scientific discourse and publications. 4. Notably, the term 'line' has been alternately used by other terminologies and communities to refer to cultures that have been immortalized - ie has attained the capacity for indefinite propagation in vitro. In this ontology, we refer to such cell lines as 'immortal cell lines', and use the term 'cell line' to indicate any culture that has been passaged.

http://purl.obolibrary.org/obo/OBI_0100062

true

http://purl.obolibrary.org/obo/IAO_0000120

http://purl.obolibrary.org/obo/IAO_0000228

http://purl.obolibrary.org/obo/CLO_0000031

http://www.geneontology.org/formats/oboInOwl#ObsoleteClass