Examination of Immunoregulatory Receptors in the Channel Catfish (Ictalurus punctatus)

• Author / Creator

  Cortes, Herman D

• In response to pathogens, immune cells induce protective effector functions, such as degranulation, phagocytosis and cytokine secretion, which are initiated by stimulatory or inhibitory immunoregulatory receptors expressed on leukocytes. Using a fish immunological model system, the focus of my thesis work was to examine immunoregulatory receptors in vertebrates by further characterizing members of the teleost Leukocyte Immune-type Receptor (LITR) family. IpLITRs share structural and phylogenetic features with certain mammalian receptors involved in activating and abrogating immune cell functions. As stimulatory IpLITR2.6b associates with signaling adaptor molecule IpFcRγ-L, I expressed a chimeric construct of IpLITR2.6b with IpFcRγ-L in mammalian immune cells to examine its functional abilities. Engagement of this receptor- adaptor induced intracellular signaling and activation of degranulation and phagocytosis. I also expressed IpLITR1.1b, a receptor previously reported to inhibit natural killer cell cytotoxicity to examine its functions further. This inhibitory receptor surprisingly facilitated phagocytosis. This represents dual functionality among select IpLITR-types, which, to our knowledge, has not been reported before in fish. Taken together, these results highlight conserved aspects of immunoregulatory receptor signaling and function while revealing new insights that may contribute to our overall understanding of immunity.

• Subjects / Keywords

  • Comparative immunology
  • Immunoregulatory receptors
  • Innate immunity
  • Cellular signaling
  • LITRs
  • Phagocytosis
  • Channel catfish

• Graduation date

  Fall 2013

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R32T2H

• 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.