Protection of humans against malaria by immunization with radiation-attenuated Plasmodium falciparum sporozoites.
During 1989-1999, 11 volunteers were immunized by the bites of 1001-2927 irradiated mosquitoes harboring infectious sporozoites of Plasmodium falciparum (Pf) strain NF54 or clone 3D7/NF54. Ten volunteers were first challenged by the bites of Pf-infected mosquitoes 2-9 weeks after the last immunization, and all were protected. A volunteer challenged 10 weeks after the last immunization was not protected. Five previously protected volunteers were rechallenged 23-42 weeks after a secondary immunization, and 4 were protected. Two volunteers were protected when rechallenged with a heterologous Pf strain (7G8). In total, there was protection in 24 of 26 challenges. These results expand published findings demonstrating that immunization by exposure to thousands of mosquitoes carrying radiation-attenuated Pf sporozoites is safe and well tolerated and elicits strain-transcendent protective immunity that persists for at least 42 weeks.
Hoffman
Stephen L
SL
Malaria Program, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20850, USA. stephen.hoffman@celera.com
Goh
Lucy M L
LM
Luke
Thomas C
TC
Schneider
Imogene
I
Le
Thong P
TP
Doolan
Denise L
DL
Sacci
John
J
de la Vega
Patricia
P
Dowler
Megan
M
Paul
Chris
C
Gordon
Daniel M
DM
Stoute
Jose A
JA
Church
L W Preston
LW
Sedegah
Martha
M
Heppner
D Gray
DG
Ballou
W Ripley
WR
Richie
Thomas L
TL
D000293:Adolescent; D000328:Adult; D000818:Animals; D009033:Culicidae / Q000469:parasitology; D004912:Erythrocytes / Q000469:parasitology; D006801:Humans; D007114:Immunization / Q000009:adverse effects; D008288:Malaria / Q000517:prevention & control*; D017780:Malaria Vaccines / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010963:Plasmodium falciparum / Q000276:immunology* / Q000528:radiation effects; D014613:Vaccines, Attenuated / Q000276:immunology
D017780:Malaria Vaccines; D014613:Vaccines, Attenuated