Evaluation of 5.1-[NANP]19, a recombinant Plasmodium falciparum vaccine candidate, in adults

Trop Geogr Med. 1992 Jan;44(1-2):9-14.


In a randomized single-blind study, 13 healthy adult volunteers were subcutaneously immunized with 2 or 3 single 50 or 400 micrograms doses of a Plasmodium falciparum recombinant vaccine candidate designated 5.1-[NANP]19. The vaccine caused transitory reactions at the injection site. Eight (62%) volunteers had a greater than or equal to 4-fold increase of antibody titer against sporozoites in immunofluorescence assay, all 13 seroconverted in IgG enzyme-linked immunosorbent assay against [NANP]50 antigen, and in 6 (46%) a lymphocyte proliferation index greater than or equal to 3 against 5.1 antigen was observed. Seven volunteers were challenged with mosquitoes infected with P. falciparum. All developed detectable parasitemia after 7 to 12 days and all received drug therapy within 24 hours. One volunteer with a cellular response to 5.1 had two negative in vitro parasite cultures before treatment, despite overt parasitemia. He was the only challenged volunteer who remained free of malaria symptoms.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Animals
  • Antibody Formation
  • Antigens, Protozoan / immunology*
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Fluorescent Antibody Technique
  • Humans
  • Injections, Subcutaneous
  • Lymphocyte Activation
  • Male
  • Middle Aged
  • Plasmodium falciparum / immunology*
  • Protozoan Proteins*
  • Protozoan Vaccines / administration & dosage
  • Protozoan Vaccines / adverse effects
  • Protozoan Vaccines / therapeutic use*
  • Vaccines, Synthetic / administration & dosage
  • Vaccines, Synthetic / adverse effects
  • Vaccines, Synthetic / therapeutic use*


  • Antigens, Protozoan
  • Protozoan Proteins
  • Protozoan Vaccines
  • QF116 antigen, Plasmodium falciparum
  • Vaccines, Synthetic
  • circumsporozoite protein, Protozoan