The first model is based on the expression of CCR7 defined two subsets of memory cells: central memory OCM) and effector memory cells (TEw)- Champagne et al.

• TcM表达CCR7,缺乏迅速反应的效应功能,但能对细胞因子或病原进行快速的反应并成熟为TEM,失去CCR7的表达,获得组织归巢受体,并大量分泌细胞因子。