PRF1 and malaria: To verify if effector functions of malaria-induced CD8+ T cells are influenced by the expression of co-inhibitory molecules, we analyzed the intracellular expression of the pro-inflammatory cytokine Interferon γ (IFN-γ) as well as Granzyme B (GrzB) and Perforin, both of which are key effector molecules for the cytotoxic function of CD8+ T cells.