What is primary cell culture?

Cells that are directly isolated from tissues using enzymatic or mechanical methods are referred to as primary cells. Primary cell culture is the process that cultures primary cells, which proliferate under appropriate conditions until they occupy desirable confluence. After that, the proliferated cells undergo sub-culturing, when they are transferred to a new culture vessel with fresh growth medium to provide more room for continued growth. After the first subculture, the primary cell culture becomes a cell line.