Andrea Hille

Lyme disease is the most common vector-borne disease in North America making it a serious public health concern. This disease is caused by the spirochete Borrelia burgdorferi (B. burgdorferi). B. burgdorferi can escape recognition of the immune system by preventing opsonization from the complement system and antibodies, therefore, preventing phagocytosis by macrophages. This characteristic makes Lyme disease difficult to treat. Understanding how B. burgdorferi can enter and accumulate in cells is essential to understanding the progression of Lyme disease. This project aims to test how skin temperature (33°C) and core body temperature (37°C) affect B. burgdorferi entering cells. Other studies have demonstrated that B. burgdorferi maximally proliferates at skin temperature (33°C) and can enter nonphagocytic 3T3 fibroblasts which model the cellular component of the skin. Based on these previous findings, it is hypothesized that more B. burgdorferi will accumulate in cells exposed to 33°C. To test this hypothesis, B. burgdorferi bacteria which expressed GFP constitutively were cocultured with 3T3 fibroblasts and exposed to either 33°C or 37°C. 3T3 cells were stained using standard immunohistochemical procedures, and slides were imaged using a confocal microscope. The results were quantified by calculating the percentage of cells with accumulated B. burgdorferi within multiple fields of view. The results of this project show that more fibroblasts accumulated B. burgdorferi at skin temperature which is consistent with the hypothesis.