SELL and infection: However, our data are consistent with a report showing a significant increase in the proportion of CD62L− CD45RO+ effector memory T cells producing multiple cytokines (IFN-γ, TNF and IL-2), but not individual cytokines, in humans protected against sporozoite challenge by experimental infection with P. falciparum sporozoites under chloroquine chemoprophylaxis, at time of challenge as compared with baseline43.