ABSTRACT: Infectious hematopoietic necrosis virus (IHNV) persistence in Sockeye Salmon: effect on brain transcriptome and response to the viral mimic poly(I:C)
Project description:To characterise the transcriptional response in brain of Sockeye Salmon (Oncorhynchus nerka) that were persistently infected with infectious hematopoietic necrosis virus (IHNV) and to determine whether carrying the IHNV affects the ability to respond to other immunological challenges we compared the brain transcriptome of IHNV carriers, IHNV-negative survivors, and naïve Sockeye Salmon that were never exposed to IHNV. In addition we determined the transcriptional changes among carriers, survivors and naïve fish in their response to the viral mimic polyriboinosinic polyribocytidylic acid (poly(I:C)), using the cGRASP 44K salmon oligoarray.
Project description:To characterise the transcriptional response in brain of Sockeye Salmon (Oncorhynchus nerka) that were persistently infected with infectious hematopoietic necrosis virus (IHNV) and to determine whether carrying the IHNV affects the ability to respond to other immunological challenges we compared the brain transcriptome of IHNV carriers, IHNV-negative survivors, and naïve Sockeye Salmon that were never exposed to IHNV. In addition we determined the transcriptional changes among carriers, survivors and naïve fish in their response to the viral mimic polyriboinosinic polyribocytidylic acid (poly(I:C)), using the cGRASP 44K salmon oligoarray. Fish that survived an immersion challenge with IHNV and time-matched control (naïve) fish that were never exposed to IHNV were reassigned into 2 tanks each at 271 days post challenge (dpc). One group each of the challenged and naïve fish received an intraperitoneal injection of poly(I:C). For controls, a group each of challenged and naïve fish were not injected. Brain tissues were sampled from each tank at 3 (274 dpc), 7 (278 dpc) and 10 (281 dpc) days after poly(I:C) injection. Based on the presence of IHNV in brain fish were assigned into “carriers” and “survivors”, i.e. fish with detectable and undetectable levels of IHNV, respectively. For transcriptomic profiling brain samples were analysed from naïve (n = 7), survivors (n = 7), and carriers (n = 5), as well as poly(I:C)-injected naïve (n = 7), poly(I:C)-injected survivors (n = 7), and poly(I:C)-injected carriers (n = 2). All analysed brain samples were collected 274 dpc (i.e. 3 d after poly(I:C) injection) with the exception of two carriers that were collected 278 dpc. The smaller sample size for carriers was a result of the few individuals that survived the exposure that ended up carrying the virus.
