Investigating the Impact of Cadmium on Immune Function and Viral Dynamics in Jamaican Fruit Bats (Artibeus jamaicensis)

Project Summary Bats are reservoirs for a variety of viruses, many of which have significance to public health, but can maintain most of these viruses without clinical disease. Evidence suggests bats experience viral shedding events during periods of stress such as during reproduction or during times of nutritional stress. This suggests other ecological stressors, such as exposure to heavy metals including cadmium (Cd), might similarly impair immune function in bats and subsequently increase viral shedding. We previously reported increased Cd concentrations in Australian frugivorous bat species which may have impacts on the health of bats. Additionally, our preliminary studies suggest Cd exposure may alter B and T cell gene expression in a dose- dependent manner and increase viral shedding, but controlled animal laboratory studies are required to fully understand the mechanisms associated with this observation. This project aims to determine the impacts of Cd exposure on immune function and viral infection dynamics in bats. Our central hypothesis is that Cd exposure will impair adaptive immune responses in a dose-dependent manner subsequently increasing viral shedding in bats. This hypothesis will be addressed through three specific aims. In aim 1, we will determine the impact of Cd exposure on immune function and BANAL-52-CoV (B52-CoV) shedding in Jamaican fruit bats. To test this hypothesis, we will expose Jamaican fruit bats to different Cd concentrations and determine impacts on T cell responses through qPCR and activation-induced marker (AIM) testing. We will then expose groups of Jamaican fruit bats to Cd and challenge them with B52-CoV to determine the effects of Cd on viral infection and shedding. In aim 2, groups of Jamaican fruit bats exposed to Cd will be vaccinated with the SARS-CoV-2 mRNA vaccine and infected with B52-CoV to determine how Cd alters T cell responses of immunized Jamaican fruit bats. In aim 3, we will determine if free-ranging Artibeus spp. in areas with increased soil Cd concentrations have an increased odds of historical or active viral infections or decreased T cell responses compared to bats in areas with lower Cd concentrations. Completion of this project will have high significance because it will determine how Cd alters immune function and viral dynamics in bats. These results may also inform public health policies to mitigate potential impacts of Cd exposure on wildlife, and other animals that could reduce the risk of pathogen spillover. This project and career development award aligns well with my current skills and career goals to become an independent investigator. It will help me expand my knowledge in the fields of immunology, metal toxicity, in vivo animal research, and to develop key administrative and writing skills required to become an independent researcher.