The International Society for Vaccines is an organization that engages, supports, and sustains the professional goals of a diverse membership in all areas relevant to vaccines - 2019 ISV Annual Congress

Paper of the Month Mar 2018

Sterile Protection Against Human Malaria by Chemoattenuated PfSPZ Vaccine

Nature. 2017 Feb 23;542(7642):445-449

Authors

Benjamin Mordmüller1, Güzin Surat1, Heimo Lagler1,2, Sumana Chakravarty3, Andrew S. Ishizuka4, Albert Lalremruata1, Markus Gmeiner1, Joseph J. Campo5, Meral Esen1, Adam J. Ruben3, Jana Held1, Carlos Lamsfus Calle1, Juliana B. Mengue1, Tamirat Gebru1, Javier Ibáñez1, Mihály Sulyok1, Eric R. James3, Peter F. Billingsley3, Natasha KC3,6, Anita Manoj3, Tooba Murshedkar3, Anusha Gunasekera3, Abraham G. Eappen3, Tao Li3, Richard E. Stafford3,6, Minglin Li3,6, Phil L. Felgner7, Robert A. Seder4, Thomas L. Richie3, B. Kim Lee Sim3,6, Stephen L. Hoffman3* & Peter G. Kremsner1*

Institute of Tropical Medicine, University of Tübingen and German Center for Infection Research, partner site Tübingen, 72074 Tübingen, Germany. Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, 1090 Vienna, Austria. Sanaria Inc., Rockville, Maryland 20850, USA. Vaccine Research Center (VRC), National Institute of Allergy and Infectious Diseases, National Institutes of Health (NIH), Bethesda, Maryland 20892, USA. Antigen Discovery Inc., Irvine, California 92618, USA. Protein Potential, LLC, Rockville, Maryland 20850, USA. Department of Medicine, University of California Irvine, Irvine, California 92697, USA.

Abstract

A highly protective malaria vaccine would greatly facilitate the prevention and elimination of malaria and containment of drugresistant parasites1. A high level (more than 90%) of protection against malaria in humans has previously been achieved only by immunization with radiation-attenuated Plasmodium falciparum (Pf ) sporozoites (PfSPZ) inoculated by mosquitoes2–4; by intravenous injection of aseptic, purified, radiation-attenuated, cryopreserved PfSPZ (‘PfSPZ Vaccine’)5,6; or by infectious PfSPZ inoculated by mosquitoes to volunteers taking chloroquine7–10 or mefloquine11 (chemoprophylaxis with sporozoites). We assessed immunization by direct venous inoculation of aseptic, purified, cryopreserved, non-irradiated PfSPZ (‘PfSPZ Challenge’12,13) to malaria-naive, healthy adult volunteers taking chloroquine for antimalarial chemoprophylaxis (vaccine approach denoted as PfSPZCVac) 14. Three doses of 5.12 × 104 PfSPZ of PfSPZ Challenge12,13 at 28-day intervals were well tolerated and safe, and prevented infection in 9 out of 9 (100%) volunteers who underwent controlled human malaria infection ten weeks after the last dose (group III). Protective efficacy was dependent on dose and regimen. Immunization with 3.2 × 103 (group I) or 1.28 × 104 (group II) PfSPZ protected 3 out of 9 (33%) or 6 out of 9 (67%) volunteers, respectively. Three doses of 5.12 × 104 PfSPZ at five-day intervals protected 5 out of 8 (63%) volunteers. The frequency of Pf-specific polyfunctional CD4 memory T cells was associated with protection. On a 7,455 peptide Pf proteome array, immune sera from at least 5 out of 9 group III vaccinees recognized each of 22 proteins. PfSPZ-CVac is a highly efficacious vaccine candidate; when we are able to optimize the immunization regimen (dose, interval between doses, and drug partner), this vaccine could be used for combination mass drug administration and a mass vaccination program approach to eliminate malaria from geographically defined areas.