Abstract
Malaria parasite transmission remains a barrier to elimination since asymptomatic individuals sustain the infectious reservoir. Transmission-blocking vaccine (TBV) candidates targeting Plasmodium falciparum (Pf) gametocyte surface proteins Pfs230 and Pfs48/45 have shown promise in clinical trials. Several vaccine candidates have been developed for these antigens, yet it is unclear which elicit the most robust and durable transmission-blocking responses. From structure-function relationships of monoclonal antibodies in complex with both antigens, we report the development of a stabilized tandem antigen chimera (STAC), which presents the most potent epitopes from Pfs230 domain 1 (Pfs230-D1) and Pfs48/45 domain 3 (Pfs48/45-D3) in a single construct, while masking non-functional epitopes using an engineered pseudo-native domain disposition. Iterative structure-guided optimization improved antigen yields and stability, while nanoparticle-based multimerization enhanced the functional transmission-reducing activity elicited by the immunogen in female mice. Immunizations with STAC genetically conjugated to self-assembling protein nanoparticles elicited antibodies with potent transmission-reducing activity comparable or superior to the multimerized Pfs230-D1 and Pfs48/45-D3. These findings establish STAC as a promising next-generation TBV candidate to disrupt malaria transmission and accelerate elimination efforts. More broadly, our results support the engineering of highly ordered and stable multi-domain antigens in a single protein as a strategy for the cost-efficient development of multi-component vaccines.
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Data availability
The biomolecular structural data generated in this study have been deposited in the RCSB Protein Data Bank under accession codes 9N8N, 9N8I, and 9N8J, and are publicly available as of the date of publication. The cryo-EM volume data has been deposited in the Electron Microscopy Data Bank under entry ID EMD-49130. This paper does not report original code. Raw SMFA data is available in the source data. Any additional information required to reanalyze the data reported in this paper is available from the corresponding author upon request. Source data are provided with this paper.
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Acknowledgments
We would like to thank Nicholas Proellochs, Wouter Graumans, Marga van de Vegte-Bolmer, Laura Pelser-Posthumus, Astrid Pouwelsen, Jacqueline Kuhnen and Jolanda Klaassen for assistance with parasite culture and mosquito infections; Samir Benlekbir and Zhijie Li from the SickKids Nanoscale Biomedical Imaging Facility for assistance and insights during cryo-EM data collection; Greg Wasney and James Magnus Jorgensen at the Structural & Biophysical Core (SBC) Facility for assistance. X-ray diffraction experiments for biomolecular crystallography were performed at GM/CA@APS, which has been funded in whole or in part with federal funds from the National Cancer Institute (ACB-12002) and the National Institute of General Medical Sciences (AGM-12006). The Eiger 16 M detector was funded by an NIH–Office of Research Infrastructure Programs High-End Instrumentation grant (1S10OD012289-01A1). This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science user facility operated for the DOE Office of Science by Argonne National Laboratory under contract DE-AC02-06CH11357. X-ray diffraction experiments were also performed at beamline CMCF-ID at the Canadian Light Source, a national research facility of the University of Saskatchewan, which is supported by the Canada Foundation for Innovation (CFI), the Natural Sciences and Engineering Research Council (NSERC), the National Research Council (NRC), the Canadian Institutes of Health Research (CIHR), the Government of Saskatchewan, and the University of Saskatchewan. The small-angle X-ray scattering instrument was accessed at the Structural and Biophysical Core Facility, The Hospital for Sick Children, and EM data was collected at the Nanoscale Biomedical Imaging Facility, The Hospital for Sick Children, supported by the Canada Foundation for Innovation and Ontario Research Fund. This work was supported by a National Institutes of Health grant (1R01AI148557-01A1 to J.F.L., R.S.M., and J-P.J.); Bill & Melinda Gates Foundation grant (OPP1156262 to N.P.K. and J-P.J.); a Canadian Institutes of Health Research Project grant (428410 to J-P.J.); and, in part, thanks to funding from the Canada Research Chair program (J-P.J.). M.M.J. is supported by the Netherlands Organization for Scientific Research (Vidi fellowship NWO project number 192.061). S.H. is supported by a Canada Graduate Scholarship - Doctoral. This work was also supported by the Division of Intramural Research (DIR), National Institute of Allergy and Infectious Diseases (NIAID).
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Experimental design was collaborative between all co-authors. Experiments were conducted by D.I., K.M., S.H., R.R., Y.S., W-C.H., R.S., K.T., G-J.v.G., E.M.L., S.C., C.M., A.S., and C.S. The manuscript was written by D.I. and J-P.J., and edited by all co-authors. Funding was secured by R.S.M., C.A.L., M.M.J., N.P.K., J.F.L., and J-P.J.
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Ivanochko, D., Miura, K., Hailemariam, S. et al. A stabilized tandem antigen chimera that elicits potent malaria transmission-reducing activity. Nat Commun (2026). https://doi.org/10.1038/s41467-026-68761-1
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DOI: https://doi.org/10.1038/s41467-026-68761-1
