Immunization with attenuated Plasmodium falciparum sporozoites (PfSPZs) has been shown to be protective against malaria, but the features of the antibody response induced by this treatment remain unclear. To investigate this response in detail, we isolated IgM and IgG monoclonal antibodies from Tanzanian volunteers who were immunized with repeated injection of Sanaria PfSPZ Vaccine and who were found to be protected from controlled human malaria infection with infectious homologous PfSPZs. All isolated IgG monoclonal antibodies bound to P. falciparum circumsporozoite protein (PfCSP) and recognized distinct epitopes in its N terminus, NANP-repeat region, and C terminus. Strikingly, the most effective antibodies, as determined in a humanized mouse model, bound not only to the repeat region, but also to a minimal peptide at the PfCSP N-terminal junction that is not in the RTS,S vaccine. These dual-specific antibodies were isolated from different donors and were encoded by VH3-30 or VH3-33 alleles that encode tryptophan or arginine at position 52. Using structural and mutational data, we describe the elements required for germline recognition and affinity maturation. Our study provides potent neutralizing antibodies and relevant information for lineage-targeted vaccine design and immunization strategies.

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We would like to thank M. Nussenzweig (Rockefeller University) and H. Wardemann (German Cancer Research Center) for providing reagents for antibody cloning and expression. This work was supported in part by the Swiss Vaccine Research Institute, by the European Research Council (grant no. 670955 BROADimmune) and by the Fondazione Aldo e Cele Daccò. J.T. is funded by the Wellcome Trust (grant no. 204689/Z/16/Z). B.S. is funded by the National Institutes of Health (grant no. F32 AI 114113). The authors would like to thank first and foremost the study volunteers for their participation in the study. We also thank the entire study team at the Bagamoyo branch of the Ifakara Health Institute and the manufacturing, quality control, regulatory and clinical teams at Sanaria, Inc. for their contributions to the conduct of the trial. We would like to thank M. Tanner (former director of the Swiss Tropical and Public Health Institute, Basel) for his vision and support of the development of the clinical trial platform enabling whole sporozoite–based malaria vaccine trials in Bagamoyo, Tanzania. D.O. and I.A.W. are funded by PATH's Malaria Vaccine Initiative under a collaborative agreement with The Scripps Research Institute and by the Bill and Melinda Gates Foundation. A.L. and F.S. are supported by the Helmut Horten Foundation. This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231. The Tanzanian Commission on Science and Technology (COSTECH), the Ifakara Health Institute, and the Swiss Tropical Public Health Institute provided funding for the clinical trial. The functional assays were supported by the Bill and Melinda Gates foundation (Investment ID: 24922). The development, manufacturing, and quality control release and stability studies of PfSPZ Vaccine and PfSPZ Challenge were supported in part by National Institute of Allergy and Infectious Diseases (NIAID) Small Business Innovation Research grant 5R44AI055229. Sanaria supported transport of PfSPZ Vaccine and PfSPZ Challenge to the study site and syringe preparation.

Author information

Author notes

    • Joshua Tan
    • , Brandon K Sack
    • , David Oyen
    • , Isabelle Zenklusen
    •  & Luca Piccoli

    These authors contributed equally to this work.

    • Claudia Daubenberger
    • , Ian A Wilson
    •  & Antonio Lanzavecchia

    These authors jointly directed this work.


  1. Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona, Switzerland.

    • Joshua Tan
    • , Luca Piccoli
    • , Sonia Barbieri
    • , Mathilde Foglierini
    • , Chiara Silacci Fregni
    • , Jessica Marcandalli
    • , Laurent Perez
    • , Luca Varani
    • , Federica Sallusto
    •  & Antonio Lanzavecchia
  2. Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK.

    • Joshua Tan
  3. Center for Infectious Disease Research, Seattle, Washington, USA.

    • Brandon K Sack
    •  & Stefan H I Kappe
  4. Department of Integrative Structural and Computational Biology, Scripps Research Institute, La Jolla, California, USA.

    • David Oyen
    •  & Ian A Wilson
  5. Faculty of Science, University of Basel, Basel, Switzerland.

    • Isabelle Zenklusen
    •  & Claudia Daubenberger
  6. Swiss Tropical and Public Health Institute, Clinical Immunology Unit, Basel, Switzerland.

    • Isabelle Zenklusen
    •  & Claudia Daubenberger
  7. Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland.

    • Mathilde Foglierini
  8. Ifakara Health Institute, Bagamoyo Clinical Trial Unit, Bagamoyo, Tanzania.

    • Said Jongo
    •  & Salim Abdulla
  9. Biochemistry Department, University of Lausanne, Epalinges, Switzerland.

    • Giampietro Corradin
  10. Institute of Microbiology, ETH Zurich, Zurich, Switzerland.

    • Federica Sallusto
    •  & Antonio Lanzavecchia
  11. Sanaria Inc., Rockville, Maryland, USA.

    • Betty Kim Lee Sim
    •  & Stephen L Hoffman
  12. Skaggs Institute for Chemical Biology, Scripps Research Institute, La Jolla, California, USA.

    • Ian A Wilson


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J.T. characterized monoclonal antibodies, analyzed the data and wrote the manuscript; B.K.S. performed in vivo assays, analyzed the data and wrote the manuscript; D.O. performed structural analysis, analyzed the data and wrote the manuscript; I.Z. collected samples, conducted in vitro assays, analyzed the data and wrote the manuscript; L. Piccoli characterized monoclonal antibodies, analyzed the data and wrote the manuscript; S.B. sequenced and expressed antibodies; M.F. performed bioinformatics analysis; C.S.F. immortalized memory B cells; J.M and L. Perez immunized mice; S.J. supervised cohorts; S.A. oversaw the clinical trial and provided PBMCs to the laboratory team; G.C. provided PfCSP peptides; L.V. designed peptide and antibody mutants; F.S. and S.H.I.K. provided supervision; S.L.H. and B.K.L.S. produced PfSPZ Vaccine and PfCSP, prepared the syringes used to immunize, and provided PfSPZ for antibody assays, including screening of monoclonal antibodies; C.D. handled cohorts and provided supervision; I.A.W. supervised structural analysis and wrote the manuscript; A.L. provided overall supervision, analyzed the data and wrote the manuscript.

Competing interests

A.L. is the scientific founder and shareholder of Humabs BioMed. F.S. is a shareholder of Humabs BioMed. B.K.L.S. and S.L.H. are salaried employees of Sanaria Inc., the developer and owner of the PfSPZ Vaccine and PfSPZ Challenge and the sponsor of the clinical trials. In addition, B.K.L.S. and S.L.H. have a financial interest in Sanaria Inc.

Corresponding author

Correspondence to Antonio Lanzavecchia.

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