Dose-Dependent Infectivity of Aseptic, Purified, Cryopreserved Plasmodium falciparum 7G8 Sporozoites in Malaria-Naive Adults

J Infect Dis. 2019 Nov 6;220(12):1962-1966. doi: 10.1093/infdis/jiz410.

Abstract

Direct venous inoculation of 3.2 × 103 aseptic, purified, cryopreserved, vialed Plasmodium falciparum (Pf) strain NF54 sporozoites, PfSPZ Challenge (NF54), has been used for controlled human malaria infection (CHMI) in the United States, 4 European countries, and 6 African countries. In nonimmune adults, this results in 100% infection rates. We conducted a double-blind, randomized, dose-escalation study to assess the infectivity of the 7G8 clone of Pf (PfSPZ Challenge [7G8]). Results showed dose-dependent infectivity from 43% for 8 × 102 PfSPZ to 100% for 4.8 × 103 PfSPZ. PfSPZ Challenge (7G8) will allow for more complete assessment by CHMI of antimalarial vaccines and drugs.

Keywords: Plasmodium falciparum; controlled human malaria infection; cryopreservation; humans.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Administration, Intravenous
  • Adult
  • Dose-Response Relationship, Immunologic*
  • Female
  • Humans
  • Malaria Vaccines / administration & dosage
  • Malaria Vaccines / adverse effects
  • Malaria Vaccines / immunology*
  • Malaria, Falciparum / immunology
  • Malaria, Falciparum / parasitology*
  • Malaria, Falciparum / prevention & control*
  • Male
  • Plasmodium falciparum / immunology*
  • Sporozoites / immunology*
  • Vaccination

Substances

  • Malaria Vaccines