RTS,S/AS02A Malaria Vaccine-Induced IgG Responses Equally Recognize Native-Like Fucosylated and Nonfucosylated Plasmodium falciparum Circumsporozoite Proteins

The RTS,S/AS02A malaria vaccine is based on the Plasmodium falciparum circumsporozoite protein (PfCSP), which is O-fucosylated on the sporozoite surface. We determined whether RTS,S/AS02A-induced immunoglobulin G (IgG) antibodies recognize vaccine-like nonfucosylated PfCSP better than native-like fucosylated PfCSP. Similar to previous vaccine trials, RTS,S/AS02A vaccination induced high anti-PfCSP IgG levels associated with malaria protection. IgG recognition of nonfucosylated and fucosylated PfCSP was equivalent, suggesting that PfCSP fucosylation does not affect antibody recognition.Clinical Trials Registration NCT00197041. The RTS,S/AS02A malaria vaccine, in which the Plamodium falciparum circumsporozoite protein is not fucosylated, induces IgG antibodies that equally recognize nonfucosylated and native-like fucosylated target antigens, suggesting that posttranslational modification by O-fucosylation does not significantly affect antibody-antigen binding.