Longitudinal characterization of immunoregulatory mechanisms and host protection in dengue virus infection

Abstract

Dengue disease is a global health problem that affects approximately 390 million people per year, in over 120 countries but no specific therapy or vaccine is currently available to effectively combat dengue virus (DENV) infection. While most of the individuals infected by DENV are asymptomatic or present uncomplicated symptoms, 5-20% of the patients develop severe dengue (SD) in several days, with life-threatening disease manifestations due to mechanisms still poorly understood. There are currently no clinically usable biomarkers to predict who will progress to SD and there are no approved treatment or safe vaccines to prevent SD. Thus, there is an urgent need to comprehensively understand the anti-DENV immune response. We recently characterized the overlap between natural DENV infection and vaccine trials, identifying candidate markers for monitoring vaccine effectiveness against DENV, and showed the landscape of T cell exhaustion in association with disease severity. In parallel, the Einav lab has collected longitudinal PBMC and serum samples from over 500 DENV infected patients and has developed a novel virus-inclusive single-cell transcriptomic (viscRNA-seq) approach to monitor the host response to DENV infection in correlation with viral abundance in dengue patients' samples. This analysis revealed molecular determinants involving regulatory and exhausted T cells that are associated with SD progression. Given the overlap in our groups' interest to unravel the pathophysiology of SD, in the BEPE proposal my goal is to elucidate the role of regulatory and exhausted T cells in SD pathogenesis, using complementary approaches developed in the Einav lab. My hypothesis is that alterations in the abundance, expression profile, and immune exhaustion of T cell subsets as well as the timing and magnitude of their responses play a role in increasing disease severity in humans and can be used as candidate targets for prognosis and treatment. In Aim 1 I will monitor the kinetics of altered cell subset abundance and RNA and protein expression profiles identified in T cell subsets in patients who progressed to SD during the disease course using single cell transcriptomic and proteomic approaches. In Aim 2 I will functionally characterize regulatory and exhausted T cell responses in patients who progressed to SD during the disease course. This project should provide insight into SD pathogenesis, and it may reveal new biomarkers to predict progression to SD and/or targets for the development of therapy or vaccine to prevent SD progression. Through this project, I will expand my training in human systems immunology and learn how to use multi-omics single cell approaches which I hope to use in the future for studying longitudinal Brazilian cohorts. (AU)