Theses and Dissertations

Issuing Body

Mississippi State University


Petrie-Hanson, Lora

Committee Member

Hanson, Larry

Committee Member

Lawrence, Mark

Date of Degree


Document Type

Graduate Thesis - Open Access


Veterinary Medical Science

Degree Name

Master of Science (M.S.)


College of Veterinary Medicine


Department of Basic Sciences


This study used rag1-/- mutant zebrafish, which lack functional T and B lymphocytes, to investigate whether innate immune cells from vaccinated mutant zebrafish demonstrate enhanced survival compared to phagocytes from naïve mutant fish. Edwardsiella ictaluri, an economically significant aquatic pathogen and the causative agent of enteric septicemia of catfish (ESC), was used for the trials. Quantification of live bacteria from sampled kidneys was accomplished via colony counts, luminescence readings, and differential DNA extractions using Ethidium Monoazide (EMA) and Propidium Monoazide (PMA) followed by qPCR. There was a general trend of less bacteria in vaccinated mutant fish. Additionally, the mortality in the vaccinated fish was less than the naïve group, suggesting that the vaccinated fish are better able to withstand the bacteria load. Giemsa-stained cytospins showed E. ictaluri exclusively within macrophages from sampled kidneys, suggesting that the macrophages are the critical site of pathogenesis in rag1-/- zebrafish.