Fig. 1

Malaria transmission-blocking vaccine concept for the prevention of community spread of malaria parasites. a Humans who receive and immunologically respond to a malaria transmission-blocking vaccine (TBV) develop antibodies that co-circulate with Plasmodium sexual stage gametocytes (P. falciparum gametocytes are shown in purple/red) during symptomatic and subclinical malaria infections. b Anopheles mosquitoes that blood feed on the immunized and infected host will pick up both the antibodies and the parasites into the mosquito midgut (red mosquito). Inside the midgut (inset, outline), the male and female gametocytes transform to gametes, then fertilize to form a motile zygote, called an ookinete. Antibodies elicited by TBVs that are taken up along with the parasite can either bind directly to the gametocyte (P230 or P48/45 [18,19,20,21,22]) or ookinete (P25 [23,24,25]) or to a critical mosquito receptor (AnAPN1 [13,14,15]) that the ookinete uses to enter the midgut cell to ensure sporogonic development continues. c By completely blocking or significantly reducing mosquito infections, TBVs prevent the cascade of secondary infections in a community when the mosquito takes another bloodmeal (uninfected, black mosquito). Homes in the community with infectious individuals are shown in dark red and homes without malaria infections are indicated in white. Middle image was adapted from Public Health Image Library