Author(s):
|
Bastiaens, G.J.H.
; Meer, M.P. van; Scholzen, A.;
Obiero, J.M.
; Vatanshenassan, M.; Grinsven, T. van; Sim, B.K.; Billingsley, P.F.; James, E.R.; Gunasekera, A.; Bijker, E.M.;
Gemert, G.J.A. van
;
Vegte-Bolmer, M.G. van de
;
Graumans, W.
;
Hermsen, C.C.
;
Mast, Q. de
;
Ven, A.J.A.M. van der
; Hoffman, S.L.;
Sauerwein, R.W.
|
Subject:
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Radboudumc 4: lnfectious Diseases and Global Health RIHS: Radboud Institute for Health Sciences Radboudumc 4: lnfectious Diseases and Global Health RIMLS: Radboud Institute for Molecular Life Sciences |
Organization:
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Medical Microbiology Internal Medicine |
Journal title:
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American Journal of Tropical Medicine and Hygiene
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Abstract:
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Immunization of volunteers under chloroquine prophylaxis by bites of Plasmodium falciparum sporozoite (PfSPZ)-infected mosquitoes induces > 90% protection against controlled human malaria infection (CHMI). We studied intradermal immunization with cryopreserved, infectious PfSPZ in volunteers taking chloroquine (PfSPZ chemoprophylaxis vaccine [CVac]). Vaccine groups 1 and 3 received 3x monthly immunizations with 7.5 x 10(4) PfSPZ. Control groups 2 and 4 received normal saline. Groups 1 and 2 underwent CHMI (#1) by mosquito bite 60 days after the third immunization. Groups 3 and 4 were boosted 168 days after the third immunization and underwent CHMI (#2) 137 days later. Vaccinees (11/20, 55%) and controls (6/10, 60%) had the same percentage of mild to moderate solicited adverse events. After CHMI #1, 8/10 vaccinees (group 1) and 5/5 controls (group 2) became parasitemic by microscopy; the two negatives were positive by quantitative real-time polymerase chain reaction (qPCR). After CHMI #2, all vaccinees in group 3 and controls in group 4 were parasitemic by qPCR. Vaccinees showed weak antibody and no detectable cellular immune responses. Intradermal immunization with up to 3 x 10(5) PfSPZ-CVac was safe, but induced only minimal immune responses and no sterile protection against Pf CHMI.
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