Figure 1.

Live attenuated pre-erythrocytic malaria vaccines tested in human volunteers. (A) In the PfSPZ strategy, parasites are irradiated while in the mosquito vector, and arrest at different times during early development (red arrows) depending on the specific mutations induced. Late liver stages are absent, and no merozoites are released (indicated in the figure by the fact that those stages are greyed out). (B) In CPS under chloroquine (CQ) coverage, parasites complete liver stage development, and erythrocyte-infective merozoites are released, but the presence of CQ prevents development past the intra-erythrocytic trophozoite stage (red arrows). (C) The p52⁻/p36⁻ GAP knockout results in very early liver stage arrest before formation of the parasitophorous vacuole (red arrow). Modified from ref. 45.