PDCD1 and infection: To better characterize the molecular signatures of the T cell response and given that chronic malaria infection results in an increased frequency of T cells expressing surface markers of exhaustion such as programmed cell death-1 (PD-1)12, we asked whether the self-resolving nature of PbNK65 hrfΔ infection could be correlated to a change in PD-1 expression on the surface of effector T cells.