Out of the Shell: Exploring The Phagocytic Capabilities of the B Cell and Isolated Lymphoid Follicle-lie Structures in the Red-Eared Slider, Trachemys Scripta

Management of immunity is crucial for survival in all living organisms. While there is a large amount of research for established model organisms, such as the mouse model, much less is known about reptiles. When compared to immunity in mammals, we discover many differences such as susceptibility to certain pathogens, alteration of immune processes due to environmental temperature, the total absence of certain lymphoid organs contained in mammals, among many others. Despite this, the reptile has shown in many studies that they are worthy systems to study immunity in an evolutionary perspective and recent studies may show that they may have therapeutic use as well. Of particular interest to our lab is the management of gut mucosal immunity and phagocytic B cells in Trachmys scripta, commonly known as the red-eared slider. The thesis work reported here focuses on projects examining both of these. Reptiles lack many lymphoid structures within the gut cavity that are crucial for maintaining homeostasis and survival in mammals. Preliminary work examining lymphoid aggregates in hatchling T. scripta, suggested that they may contain lymphoid structures similar to those known as isolated lymphoid follicles in mammals. Our investigation determined that these structures, like the isolated lymphoid follicle, are composed of B cell aggregates, able to respond to enteric bacteria colonization, and increase in quantity as you progress distally within the small intestine. It is important to note that is the first time these B cell structures have been shown in a reptile. We also sought to understand the phagocytic capabilities of B cell in the red-eared slider. We hoped to learn if these cells possessed the ability to recognized different pathogens (Gram (-/+) and fungal particles), determine the sizes limitations of consumed particles, and also whether they had regulatory qualities. Unfortunately, we encountered many technical difficulties coupled with issues in the bioparticles particles we chose, which resulted in the absence of any productive data collection. It is our hope to pursue this study in the future. Overall, these studies aid in the understanding of the reptile immune system