CHARACTERIZATION OF INNATE RESPONSES INDUCED BY DSRNA FORMULATED WITH CATIONIC NANOPARTICLES IN RAINBOW TROUT
Kayla Samms, Wilfrid Laurier University
Kayla Samms1, Tamiru Alkie1, Jondavid de Jong1,2, Kristof Jenik1, Karl Klinger2, Stephanie DeWitte-Orr1
1Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON
2Mirexus Biotechnologies, Guelph, ON
The modulation of innate immunity by pathogen-associated molecular patterns (PAMPs), or synthetic mimics, that are recognized by host cell surface or intracellular receptors has profound effects on the generation of a desired innate immune response. Polyinosinic:polycytidylic acid (polyI:C) is a synthetic double stranded RNA (dsRNA) molecule known for inducing type I interferons (IFNs), interferon stimulated genes (ISGs), and an antiviral state in teleost species, following parenteral injection. We hypothesized that both local and systemic innate immune responses induced by poly(I:C) could be enhanced by oral delivery with a biodegradable, nontoxic nanoparticle (NP) in rainbow trout. Individually anesthetized rainbow trout received an oral gavage containing a meal of ground commercial trout pellets moistened with either water, the dsRNA-NP complex or a free dsRNA solution. Forty-eight hours after the first gavage, the fish were also boosted orally with the same formulations as indicated above. At 24 and 48hr postprimary gavage and at 24hr and 7 days post-boost, fish were euthanized and the expression of IFN1 and ISGs (vig-3, Mx1) were quantified in three portions of the intestine (proximal, middle and distal) and head kidney by qPCR. The results indicated that the dsRNA-NP complex induced a higher level of expression of IFN1 and ISGs in almost all segments of the intestine and head kidney. Additionally, in the intestine, none of the formulations induced histopathological lesions. The results of this study have significant implications for the aquaculture industry to exploit innate immunity as the primary defense mechanisms against viral pathogens.