The importance of identifying antigen-specific T-cell memory phenotypes (i.e. using memory and differentiation markers) and effector functions (i.e. cytokine and granzymes/perforin) in response to malaria has begun to be explored in malaria-naïve volunteers participating in phase I trials of MSP-1 (62) and in animal models of circumsporozoite surface protein (CSP), the leading pre-erythrocytic stage malaria vaccine candidate (53). Here, PRF1 is linked to malaria.