Effect of the malaria vaccine Combination B on merozoite surface antigen 2 diversity

摘要: Extensive genetic polymorphism is generally found in Plasmodium falciparum surface antigens. This poses a considerable obstacle to the development of malaria vaccine. In order assess possible effects polymorphic vaccine, we have analyzed diversity parasites collected course phase 2b field trial blood stage vaccine Combination B Papua New Guinea. The full-length 3D7 allele merozoite protein 2 (MSP2) was included as one three subunits. Vaccinees had lower prevalence carrying 3D7-type (corresponding that vaccine) and selection appeared favour alternative FC27-type alleles resulting higher incidence morbid episodes associated with parasites. We sequenced MSP2 detected study participants after vaccination identify breakthrough genotypes. observed both repetitive family-specific domains, but occurring recipients were no different from those placebo recipients. A phylogenetic analysis showed clustering infections repeat unit present molecule occurred number area also vaccinated individuals. Thus anti-repeat immune response did not lead elimination same unit. conclude conserved epitopes domain most important determinants effect against new hypervariable domains subject selective