A human monoclonal antibody blocks malaria transmission and defines a highly conserved neutralizing epitope on gametes.

Coelho, Camila H; Tang, Wai Kwan; Burkhardt, Martin; Galson, Jacob D; Muratova, Olga; Salinas, Nichole D; Alves E Silva, Thiago Luiz; Reiter, Karine et al. · Nat Commun · 2021

basic_science · Level V

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Abstract

Malaria elimination requires tools that interrupt parasite transmission. Here, we characterize B cell receptor responses among Malian adults vaccinated against the first domain of the cysteine-rich 230 kDa gamete surface protein Pfs230, a key protein in sexual stage development of P. falciparum parasites. Among nine Pfs230 human monoclonal antibodies (mAbs) that we generated, one potently blocks transmission to mosquitoes in a complement-dependent manner and reacts to the gamete surface; the other eight show only low or no blocking activity. The structure of the transmission-blocking mAb in complex with vaccine antigen reveals a large discontinuous conformational epitope, specific to domain 1 of Pfs230 and comprising six structural elements in the protein. The epitope is conserved, suggesting the transmission-blocking mAb is broadly functional. This study provides a rational basis to improve malaria vaccines and develop therapeutic antibodies for malaria elimination.

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