Long-term persistence of sterile immunity in a volunteer immunized with X-irradiated Plasmodium falciparum sporozoites.
Three volunteers were immunized by repeated exposure to the bites of Plasmodium falciparum-infected, X-irradiated mosquitoes to characterize immunologic responses and duration of protective immunity. A primary series of immunizations had been shown previously to induce sterile immunity in these volunteers against sporozoite-induced P. falciparum malaria. In the current study, antibodies to sporozoites circulated at high levels for at least 9-12 months after the volunteers were administered booster bites from X-irradiated infective mosquitoes. One volunteer challenged a second time with P. falciparum 9 months after his last immunization was again shown to be protected, whereas all 5 control subjects developed patent infections. These results set a new standard for persistence of sterile immunity against experimental P. falciparum infection.
Department of Medicine (Division of Geographic Medicine, University of Maryland School of Medicine, Baltimore 21201.
R
R
Edelman
S L
SL
Hoffman
J R
JR
Davis
M
M
Beier
M B
MB
Sztein
G
G
Losonsky
D A
DA
Herrington
H A
HA
Eddy
M R
MR
Hollingdale
D M
DM
Gordon
D000328:Adult; D000818:Animals; D000852:Anopheles; D000913:Antibodies, Protozoan / Q000097:blood; D001733:Bites and Stings; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D016778:Malaria, Falciparum / Q000276:immunology* / Q000517:prevention & control; D008297:Male; D010963:Plasmodium falciparum / Q000276:immunology* / Q000528:radiation effects; D016052:Protozoan Vaccines / Q000276:immunology*; D013997:Time Factors; D014613:Vaccines, Attenuated / Q000276:immunology; D014965:X-Rays
D000913:Antibodies, Protozoan; D016052:Protozoan Vaccines; D014613:Vaccines, Attenuated