Malaria Vaccines Targeting Pfs25 Antigen in Parasite Mosquito Stages to Block Transmission

Transmission of malaria involves Anopheles mosquitoes as the vectors of the Plasmodium parasite. The malaria eradication program includes the distribution of insecticide-treated bednets. However, the Anopheles mosquitoes have developed insecticide resistance hence it is necessary to find other modalities to eradicate the disease. Because the parasites undergo several stages in the mosquito midgut before developing into infective stages that migrate to the salivary gland, it is of interest to target the mosquito stages in vaccination to block the transmission. Human vaccination with the antigen of the mosquito stages may induce the production of specific antibodies against the stages that might be transferred into the mosquito during blood meal, binding with the antigen of the mosquito stages in the midgut and subsequently disrupting the development of the parasite. Such a vaccine is called a transmission-blocking vaccine (TBV). An effective TBV should induce a high titer of antibody for a long time. One of the leading antigens is Pfs25. Here, we review the update of TBV development targeting Pfs25, advances in the transmission-blocking assay, and challenges in the development of TBVs.