CD4 and malaria: Mathematical modeling of a Phase IIb trial in which malaria naïve volunteers were given the RTS,S vaccine formulated in either AS01B or AS02A (Kester et al., 2009), suggested that the bulk of protection comes from high levels (100–200 μg/ml) of anti-repeat antibodies, aided by robust CD4+ T cell responses (White et al., 2013).