You don't actually have to kill an [immune] cell to modify its metabolism
Alternative energy sources
Activated immune cells change what they consume and which metabolic pathway they use to break down that fuel to produce energy-carrying ATP. Some types load up on glucose, increasing glycolysis, and they consume more glutamine. Fatty acids remain a staple for other cells, which still depend on oxidative phosphorylation.
http://www.sciencemag.org/news/2018/03/treat-some-diseases-researchers-are-putting-immune-cells-diet?utm_campaign=news_daily_2018-03-30&et_rid=389974365&et_cid=1942780