Viviana Pinedo Cancino, MSc, PhD
Nominated From: University of Washington
Research Site: Peru
Research Area: HIV/AIDS; Malaria
Primary Mentor: Dr. James Kublin
Identifying naturally acquired immune responses against Plasmodium falciparum and Plasmodium vivax infection in a region of low malaria endemicity
Regions with low transmission of malaria due to Plasmodium falciparum (PF) or Plasmodium vivax (PV), such as Iquitos, Peru, are ideally suited for studying naturally acquired antimalarial immunity. Malaria infections rarely overlap, which allows studying and monitoring the immune response to a single infection. This study will conduct a retrospective analysis using a database with clinical and epidemiology of stored samples collected during 2011 and 2013 from a longitudinal cohort study in Zungarococha, known as the MIGIA project, which has approximately 2,200 participants. We have identified 100 homogeneous infections and 51 heterogeneous infections that will be include in this study. To better understand the immune response in these individuals, we propose the following specific aims:
1. Characterize antibody response dynamics BEFORE, DURING and AFTER INFECTIONS by PF.
2. Characterize antibody response dynamics BEFORE, DURING and AFTER INFECTIONS by PV.
3. Compare the impact of having two sequential infections of homologous or heterologous malaria species infections, and explore how the immune response in the second infection is impacted by the first infection. The principle hypothesis is that the response in the second infection will differ depending upon whether the two successive infections are homogeneous in species (PV and then PV or PF and then PF) or heterogeneous in species (PF and then PV or PV and then PF).
The development of an efficacious malaria vaccine requires a greater understanding of natural immunity developed against malaria. How natural immunity develops and is maintained, and perhaps enhanced by heterologous or homologous species exposure, is an unanswered question of major significance. This study in low transmission malaria would allow us to better understand the antibody responses in children and adults, and its association with clinical immunity. Furthermore, knowing if prior infections have an effect upon natural immune responses, will determine if prior malaria infection is associated with higher concentrations of antiPlasmodium antibodies at time of infection or longer lasting antiPlasmodium antibody levels after infection. Information regarding the dynamics of this immune response, differences in the immune response at time of infection by antigen type, and effect of successive infections that are heterogeneous versus homogenous will help advance vaccine development. Findings from this project will provide information that will advance our understanding of immune responses during natural malaria infections and inform an upcoming vaccine study of experimental homogenous and heterogeneous exposure to malaria.