Plant & Animal Genomes XV Conference Plant & Animal Genomes XV ConferenceJanuary 13-17, 2007
Town & Country Convention Center
San Diego, CA
Kristina M. Miller , Shaorong Li , Karia H. Kaukinen , Norma Ginther , Jon Richard , Garth Traxler
Infectious hematopoietic necrosis virus (IHNV) is endemic to Pacific salmon (Oncorhynchus spp.) but species vary in their degree of susceptibility. In addition, Atlantic salmon (Salmo salar), introduced to British Columbia for aquaculture, are highly susceptible to the IHN virus. Species-specific differences in susceptibility may result from transcriptional responses to the virus. To test this hypothesis, four salmon species were challenged via intraperitoneal injection with IHNV strain 93-057, and cDNA from head kidney tissue collected at multiple time points after challenge was analysed using the GRASP 16,005 feature microarrays. Three to four times as many genes were differentially regulated in the two most susceptible species, S. salar and O. nerka, compared to less (O. keta) or not (O. kisutch) susceptible species. For many immunological pathways (e.g. endosomal transport, complement mediated lysis, interferon inducible responses, and T-cell activation), the degree of upregulation was positively correlated with susceptibility. Maturation to an adaptive cellular immune response was observed only in the two most susceptible species. Pathways exclusive to less susceptible species were also identified (e.g. defensins, IL-1, pentraxin SAP and the alternative complement pathway). Although O. kisutch responded to an “invader” signal, none of the pathways involved intracellular recognition, suggesting that the virus did not gain entry into cells. In conclusion, differences in susceptibility do not stem from the strength of the host immunological response, but instead result from species-specific differences in viral entry, and perhaps differences in the ability of the virus to co-opt the cellular machinery for its own purposes.