Protective antibodies target cryptic epitope unmasked by cleavage of malaria sporozoite protein.

Dacon, Cherrelle; Moskovitz, Re'em; Swearingen, Kristian; Da Silva Pereira, Lais; Flores-Garcia, Yevel; Aleshnick, Maya; Kanatani, Sachie; Flynn, Barbara et al. · Science · 2025

basic_science · Level V

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Abstract

The most advanced monoclonal antibodies (mAbs) and vaccines against malaria target the central repeat region or closely related sequences within the <i>Plasmodium falciparum</i> circumsporozoite protein (PfCSP). Here, using an antigen-agnostic strategy to investigate human antibody responses to whole sporozoites, we identified a class of mAbs that target a cryptic PfCSP epitope that is only exposed after cleavage and subsequent pyroglutamylation (pGlu) of the newly formed N terminus. This pGlu-CSP epitope is not targeted by current anti-PfCSP mAbs and is not included in the licensed malaria vaccines. MAD21-101, the most potent mAb in this class, confers sterile protection against <i>Pf</i> infection in a human liver-chimeric mouse model. These findings reveal a site of vulnerability on the sporozoite surface that can be targeted by next-generation antimalarial interventions.

Medical subject headings