[HTML][HTML] Safety, immunogenicity, and protective efficacy of intradermal immunization with aseptic, purified, cryopreserved Plasmodium falciparum sporozoites in …

GJH Bastiaens, MPA van Meer… - The American journal …, 2016 - ncbi.nlm.nih.gov
GJH Bastiaens, MPA van Meer, A Scholzen, JM Obiero, M Vatanshenassan, T van Grinsven…
The American journal of tropical medicine and hygiene, 2016ncbi.nlm.nih.gov
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 3× monthly immunizations with 7.5× 10 4
PfSPZ. Control groups 2 and 4 received normal saline. Groups 1 and 2 underwent CHMI (# …
Abstract
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 3× monthly immunizations with 7.5× 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× 10 5 PfSPZ-CVac was safe, but induced only minimal immune responses and no sterile protection against Pf CHMI.
ncbi.nlm.nih.gov