A 'cell culture' as used here referes to a new lineage of cells in culture deriving from a single biological source.. New cultures are established through the initial isolation and culturing of cells from an organismal source, or through changes in an existing cell culture or line that result in a new culture with unique characteristics. This can occur through the passaging/selection of a primary culture into a secondary culture or line, or experimental modifications of an existing cell culture or line such as an immortalization process or other stable genetic modification. This class covers establishment of cultures of either multicellular organism cells or unicellular organisms.