NF135.C10: a new Plasmodium falciparum clone for controlled human malaria infections

Abstract

We established a new field clone of Plasmodium falciparum for use in controlled human malaria infections and vaccine studies to complement the current small portfolio of P. falciparum strains, primarily based on NF54. The Cambodian clone NF135.C10 consistently produced gametocytes and generated substantial numbers of sporozoites in Anopheles mosquitoes and diverged from NF54 parasites by genetic markers. In a controlled human malaria infection trial, 3 of 5 volunteers challenged by mosquitoes infected with NF135.C10 and 4 of 5 challenged with NF54 developed parasitemia as detected with microscopy. The 2 strains induced similar clinical signs and symptoms as well as cellular immunological responses.

Clinical trials registration: NCT01002833.

Figure 1.

Parasite kinetics of Plasmodium falciparum strains NF135.C10, and NF54 assessed by quantitative real-time polymerase chain reaction. Volunteers were infected by bites of mosquitoes infected with either NF135.C10 or NF54. A, Parasitemia of volunteers until thick smear positivity; data are shown as geometric means and 95% confidence intervals for volunteers successfully infected with NF135.C10 (red) or NF54 (black) and historical controls infected with NF54 (gray area; n = 48). B, Parasitemia of volunteers at the time of smear positivity and subsequent start of treatment (T), followed up for 3 days and finally at 28 days after infection; data are shown as geometric means and 95% confidence intervals for volunteers successfully infected with NF135.C10 (red; n = 3) or NF54 (black; n = 4).