Differences in the transcriptomic response of human adult, neonatal, and older adult monocytes to Listeria monocytogenes infection

Listeria monocytogenes (Lm) kills up to 60% of infected newborns and adults >60 years of age but is asymptomic is most young adults. Monocytes are central to effective host defense against Lm. We hypothesize that age-dependent, pathway-specific differences in the ability of the monocyte to respond to Lm explain the increased risk of the newborn and older adult to severely suffer or die from Lm infection. To delineate age-dependent differences in innate responses that lead to differential infectious outcome, monocytes were isolated from cord blood (newborn) and peripheral blood (young and older adults) and infected with Lm. RNA was collected to determine age-dependent transcriptomic changes upon infection. Total RNA was isolated from purified human monocytes from 6 adult, 6 cord , 6 older adult blood donors that were infected with wild-type Listeria monocytogenes at a multiplicity of infected (MOI)=5 for 2 and 6 hr.