PROJECT SUMMARY 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. Dr. Friedman-Klabanoff’s long-term goal is to become an independent clinical and translational researcher dedicated to the development of a malaria vaccine, applying immunology and data science to inform and optimize vaccine development. To gain the skills necessary to achieve this goal, Dr. Friedman-Klabanoff proposes a career development plan that includes mentoring from Drs. Miriam Laufer, Shannon Takala Harrison, Michael Cummings, Andrea Berry, Kathleen Neuzil, and John Adams, leaders in the fields of international research design and leadership, molecular epidemiology, data science for analysis of large data sets, use of peptide microarrays to study malaria, vaccinology, and in vitro models of pre-erythrocytic immunity. This project will utilize samples and data from a cohort study of malaria in Malawi led by Dr. Laufer, the primary mentor for this proposal. 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. Aim 1 of this proposal will be to identify serologic responses associated with natural protection against P. falciparum infection after exposure to 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. Aim 2 of this proposal is to assess the functional role of antibodies targeting P. falciparum pre-erythrocytic antigens of interest. B- and T- cell epitope prediction tools will be used to find predicted epitopes in pre-erythrocytic proteins and their variants, a...