Human lgA Monoclonal Antibody that Targets a Conserved Site on the Plasmodium Falciparum Circumsporozoite Protein

Scientists at NIAID have isolated MAD2-6, an IgA antibody active against Plasmodium falciparum sporozoites, the infectious agent of malaria. In 2019, the majority of the 229 million cases resulted from P. falciparum infections. Because P. falciparum has a complex lifecycle during human infection, most advanced malaria vaccine candidates and current chemoprophylaxis drugs can confer only partial, short-term protection in malaria-endemic areas. Thus, the MAD2-6 antibody could be used alone or in combination with current technology.

MAD2-6 binds to a unique epitope overlapping with region I, a functionally important region of the Plasmodium falciparum circumsporozoite protein (PfCSP). This binding site of PfCSP is a previously unknown target for protective antibodies, which may be useful as a new target. Monoclonal antibodies are promising tools for prevention of malaria and could replace or be combined with malaria chemoprevention in areas with seasonal malaria.