Serological markers of natural immunity to Plasmodium falciparum infection

Plasmodium falciparum is the most common and deadly cause of malaria. An effective malaria vaccine has the potential to make a pivotal change in malaria control and eradication. For a vaccine to contribute significantly to malaria eradication, it must target the early, pre-erythrocytic part of the lifecycle to block both symptomatic disease and asymptomatic infection, which perpetuates transmission. Naturally acquired immunity to pre- erythrocytic infection is acquired with exposure but remains poorly understood and continues to impede vaccine efforts. DeAnna Friedman-Klabanoff, M.D., a pediatric infectious disease specialist at the University of Maryland School of Medicine, developed this career development award proposal to use novel high-throughput tools to define naturally acquired humoral immunity to diverse pre-erythrocytic epitopes associated with protection, which could lead to novel vaccine candidates.

Household members were followed monthly for detection of malaria infection and mosquitoes were collected from the houses to identify bloodmeal sources. Bloodmeal sources will be identified by matching the human DNA found in the mosquito bloodmeals to DNA from enrolled participants . Mosquito salivary glands will also be tested for P. falciparum infection to determine if the mosquitoes were infectious. Children will be defined as protected or infected based on whether they develop blood-stage infection during the month after an infectious bite. Serum from the day of exposure will be probed on a custom-developed peptide microarray designed from diverse, field-derived sequences to characterize pre-exposure immunity to pre-erythrocytic antigens.

B- and T- cell epitope prediction tools will be used to find predicted epitopes in pre-erythrocytic proteins and their variants, and in vitro liver models will be used to assess the functional role of antibodies to these epitopes to validate and down select the potential epitopes. The practical implications of this work will be to identify promising epitopes that are targets of protective immunity.

NIH project details

Enabling Technologies & Assays

Jul 2021 — Jun 2026

$365,774

United States