BRIEF LIFE. “In the adult animal, unwanted cells are eliminated through PCD when they are no longer needed. For instance, during an immune response there is a rapid production of lymphocytes which respond to a specific pathogen. These lymphocytes have to be eliminated after the pathogen has been cleared. For these reason, these cells are ‘programmed’ to eliminate themselves after a few days of life.” (PCD = programmed cell death).
https://celldeath.files.wordpress.com/2010/11/lopezself_munoz.pdf