cells that have been isolated from some organismal source, expanded in culture, but not undergone a complete passaging (ie are still in culture, or have been lifted from culture and frozen in aliquots for future use)
Spleen cells put directly into culture; Cold storage of biopsies from wild endangered native Chilean species in field conditions and subsequent isolation of primary culture cell lines. In Vitro Cell Dev Biol Anim. 2008 Jul 2. PMID: 18594934
consider if we really want to be so strict here . . . ie maybe we we say that they have not been output from an 'establishing cell line' process, but in some cases a passage or two may be allowed for a primary culture. the establishing of a line requires some procedss that attains a degree of homogeneity in the culture.
2013-6-5 MHB: This OBI class was formerly called 'primary cell culture', but label changed and definition updated following CLO alignment work. Previous definition: 'a primary cell culture is a cell culture where the cells derive from a fresh tissue source.'