Experimental Human Malaria Infection After Immunization With Plasmodium Falciparum Sporozoites Under Chloroquine Prophylaxis

Malaria is one of the major infectious diseases in the world with a tremendous impact on the quality of life significantly contributing to the ongoing poverty in endemic countries. It causes almost one million deaths per year, the majority of which are children under the age of five. The malaria parasite enters the human body through the skin, by the bite of an infected mosquito. Subsequently, it invades the liver and develops and multiplies inside the hepatocytes. After a week, the hepatocytes burst open and the parasites are released in the blood stream, causing the clinical phase of the disease. As a unique opportunity to study malaria immunology and efficacy of immunisation strategies, a protocol has been developed in the past to conduct experimental human malaria infections (EHMIs). EHMIs generally involve small groups of malaria-naïve volunteers infected via the bites of P. falciparum infected laboratory-reared Anopheline mosquitoes. Although potentially serious or even lethal, Plasmodium falciparum (P.falciparum) malaria can be radically cured at the earliest stages of blood infection where risks of complications are virtually absent. The investigators have shown previously, that healthy human volunteers can be protected from a malaria mosquito challenge by immunization with mosquito-bites under chloroquine prophylaxis (CPS immunization). However, it is unknown whether this protection is based on immunity directed towards the liver- or the blood stage of the disease. For future development of vaccines and understanding of protective immunity to malaria, it is important to investigate at which level protective immunity is generated by CPS immunization. Therefore, we aim to investigate whether CPS immunization confers protection to a blood-stage challenge.