Date of Award
5-2023
Degree Type
Honors College Thesis
Academic Program
Biological Sciences BS
Department
Biological Sciences
First Advisor
Dr. Shahid Karim
Advisor Department
Biological Sciences
Abstract
Ticks are a diverse group of obligate blood-feeding (hematophagous) arthropods that transmit a wide array of human and animal pathogens. These pathogens have caused an increase in tick-borne diseases that pose a significant threat to public health without preventative measures. These pathogens interact with the tick immune system upon uptake, which is primarily divided into humoral and cellular components. Cellular immunity in ticks encompasses several pathogen-eliminating mechanisms including phagocytosis. These mechanisms are mediated by the action of immune cells, commonly referred to as hemocytes, which are analogous to mammalian white blood cells. This study utilized a combination of morphological, functional, and pharmacological assays to characterize the hemocyte population and hemocyte functions in Amblyomma americanum ticks. Our study revealed five distinct hemocyte populations, which experienced individual changes in proportion to the total hemocyte number following blood meal. A phagocytosis assay using in-vivo fluorescent beads allowed us to distinguish between phagocytic and non-phagocytic hemocytes. In addition, the use of clodronate liposomes, which depletes professional phagocytic hemocytes, led to increased tick mortality following Escherichia coli and Staphylococcus aureus infection. This study advances our understanding of tick hemocyte function and cellular immunity in a blood-feeding arthropod.
Copyright
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Recommended Citation
Hanson, Julia, "Morphological and Functional Classification of the Amblyomma americanum (Lone Star Tick) Hemocytes" (2023). Honors Theses. 1148.
https://aquila.usm.edu/honors_theses/1148