查看文章

We evaluated repeated blood-stage infections with Plasmodium falciparum in eight Aotus lemurinus lemurinus monkeys. Over the course of seven infections with 104 P. falciparum (the Vietnam Oak Knoll [FVO] strain), the pre-patent period lengthened from 8.2 to 30.8 days; the peak parasitemia decreased from 4.5 105 to 0 parasites/l (Challenges 6 and 7), and the requirement for treatment decreased from 100% to 0%(Challenges 3 to 7). Five weeks after the seventh FVO challenge, the eight immune and three naıve monkeys received 104 parasitized erythrocytes infected with P. falciparum (CAMP strain). The three control animals experienced uncontrolled parasitemias reaching between 4.8 and 7.7 105 parasites/l (pre-patency 6.3 days) and all required drug treatment; six of the eight immune monkeys became parasitemic (pre-patency 8.8 days), but self-cured. Two of three of the monkeys having the greatest reductions in hematocrit (50–60%) also had the highest parasitemias (104 parasites/l) before self-curing. Repeated homologous infections induced sterile immunity to homologous challenge; during heterologous challenge the monkeys developed clinically relevant, but not life-threatening, parasitemias and anemia.