Figure 4: Response to infection and the recovery of homeostasis.

The case of the murine CD8+ T-cell response to LCMV is depicted. After viral infection, naı ¨ve CD8+ T cells that recognize LCMV epitopes may go through 13 or more divisions within 8 days, producing massive numbers of effector cells. When antigen is cleared, most of the effector cells die, leaving an expanded population of LCMV-specific T cells, which join the memory pool.