Temperature-dependent regulation of gene expression in poly (I:C)-treated Japanese flounder, Paralichthys olivaceus

The Innate Immune Response of Atlantic Salmon (Salmo salar) Is Not Negatively Affected by High Temperature and Moderate Hypoxia

“…Taken together, our results indicate that temperatures up to 20 • C hasten the induction, but do not alter the magnitude of, immune-related transcript expression levels in salmon. An earlier increase in expression levels of immune-related genes at high temperatures was also observed by Thanasaksiri et al (102) for Japanese flounder (Paralichthys olivaceus) injected with polyinosinic:polycytidylic acid [poly (I:C)] at 25 vs. 15 • C, and by Hori et al (103) in Atlantic cod injected with formalin-killed A. salmonicida at 16 vs. 10 • C. Similarly, mx and stat1 transcripts were strongly up-regulated in Japanese flounder injected with poly (I:C) at 25 • C at 3 HPI, whereas at 15 • C, the genes were only up-regulated at 24 HPI (98). Furthermore, the magnitude and timing of expression observed in our study are consistent with data obtained by a number of other authors: for tnfa1, tnfa2, il1b, and il8 in peripheral blood leukocytes and head kidney homogenates of southern Bluefin tuna (Thunnus thynnus) stimulated with LPS at 25 and 18 • C (27); by Raida and Buchmann (31) when measuring the expression of il6, il10, ifng, tnfa, and tgf in the spleen of rainbow trout acclimated for 8 weeks at 25 or 15 • C and bath vaccinated with Y. ruckeri; and as shown by Kaneshige et al (104) in Japanese flounder injected with formalin-killed Edwarsiella tarda at 25 and 15 • C for il1b, hamp, and ifng.…”

“…However, information about how long-term acclimation to high temperatures affects the innate immune response, specifically the expression of immune-related genes, is still limited. The majority of studies in this area suggest that high temperatures induce an earlier expression of immune-relevant genes (14,98). However, studies have often compared immunerelated gene expression in fish held at different temperatures at the same time point (25) or only at a limited number of time points (99); which could potentially have led to questionable conclusions.…”

“…However, studies have often compared immunerelated gene expression in fish held at different temperatures at the same time point (25) or only at a limited number of time points (99); which could potentially have led to questionable conclusions. In addition, many studies in fish have only investigated the effects of short-term exposure to high temperature on immune-related gene expression (29,44,98,100,101). In this study, water temperature was slowly increased from 12 to 20 • C under conditions of normoxia and moderate hypoxia [i.e., mimicking what salmon at cage-sites may face during the summer months (10)(11)(12)37)], and the salmon were sampled at 6, 12, 24, and 48 HPI with Forte V II or PBS.…”

Effects of Peptidoglycan and Polyinosinic: Polycytidylic Acid on the Recombinant Subunit Vaccine Efficacy Against <i>Edwardsiella tarda</i> in Japanese Flounder <i>Paralichthys olivaceus</i>

“…PolyIC enhances antiviral immunity in various fish species, including Japanese flounder (Zhou et al, 2014;Thanasaksiri et al, 2015). It is recognized by Toll-like receptor 3 and other receptors and induces type I IFN and ISGs (Ohtani et al, 2011;Hikima et al, 2012;Hwang et al, 2012).…”

“…Recently, adjuvant effects of type I IFN in fish have been reported (Martinez-Lopez et al, 2014;Chang et al, 2015). Type I IFN is induced by a viral infection and the administration of double-stranded RNA, such as polyinosinic:polycytidylic acid (polyIC), and induces IFNinducible genes (ISGs), including Mx proteins in many fish species, such as Japanese flounder (Zhou et al, 2014;Thanasaksiri et al, 2015). ISGs confer antiviral activities and protect the host from viral infection.…”