Analysis of the acute phase response in goldfish (Carassius auratus L.) infected with Trypanosoma carassii

• Author / Creator

  Kovacevic, Nikolina

• The innate immune response is a fundamental defense mechanism in bony fishes and a crucial component of innate immunity is the acute phase response (APR). The APR is a systemic and/or local response to any injury, infection, or trauma and is characterized by a change in the blood composition of acute phase proteins (APPs). In both veterinary and human medicine, APPs are well characterized, however the functional significance of fish APP orthologs has not been fully elucidated. My master’s research focused on the immunological interactions between T. carassii and its goldfish host with a focus on the APR. The gene expression profile of several APPs in the kidney, liver and spleen of T. carassii infected goldfish was examined during the acute and chronic phases of infection. The genes encoding for C-reactive Protein (CRP) and Serum Amyloid A (SAA) were highly expressed in the tissues of goldfish during the course of T. carassii infection. Consequently, recombinant goldfish CRP and SAA were generated and functionally characterized. Recombinant goldfish CRP (rgfCRP) enhanced complement-mediated killing of trypanosomes in vitro, and the lysis of the parasites was enhanced after addition of immune serum to cultures. rgfCRP did not affect the production of reactive oxygen and nitrogen intermediates by monocytes and macrophages, respectively. Furthermore, unlike mammalian recombinant CRP, rgfCRP did not act as an opsonin to enhance phagocytosis of T. carassii by macrophages. Recombinant goldfish SAA (rgSAA) treated monocytes and macrophages exhibited differential gene expression of select immune genes. rgSAA induced gene expression of both pro-inflammatory (TNFα1, TNFα2) and anti-inflammatory cytokines (IL-10, TGFβ) in monocytes, and IL-1β1 and SAA gene expression macrophages. rgSAA was chemotactic to macrophages and neutrophils, but not monocytes. rgSAA had no effect on respiratory burst in monocytes, however, it suppressed nitric oxide production in macrophages exposed to heat-killed Aeromonas salmonicida. rgSAA displayed antibacterial properties against Escherichia coli in a concentration dependent manner. The results of my thesis research present the first comprehensive analysis of the acute phase response during the course of a protozoan infection of bony fish. Additionally, it also presents a first comprehensive analysis of two major acute phase proteins, CRP and SAA, in bony fish.

• Subjects / Keywords

  • Acute phase proteins
  • Trypanosoma carassii
  • Serum Amyloid A
  • Goldfish
  • Acute phase response
  • C-reactive protein

• Graduation date

  Spring 2016

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3H70854D

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.