Temperature-dependent viral replication and antiviral apoptotic response in viral haemorrhagic septicaemia virus (VHSV)-infected olive flounder (Paralichthys olivaceus)

Behavioral fever in ectothermic vertebrates

“…The study of Boltaña et al (2013) suggested that behavioral fever induced by injection of zebrafish with synthetic dsRNA (poly I:C) and demonstrated by shift in thermal preference from 29.4 C to 33.1 C, promotes the emergence of a highly specific anti-viral immune response by induction of the transcription of specific genes in brains of zebrafish (Boltaña et al, 2013). This is in accordance with previous observations that higher temperature has a positive effect on viral clearance in fish (Avunje et al, 2012;Novoa et al, 2010). Moreover, behavioral fever significantly affected transcription of neuroregulatory receptors and in particular components of the inflammatory reflex, a7 nicotinic acetylcholine receptor (a7nAChR) and acetylcholinesterase (AChE) in the brain, suggesting that behavioral fever plays a role in inhibition of antiinflammatory reflex and provides conditions for increased antiviral responses (Boltaña et al, 2013).…”

Transcriptional analysis of olive flounder lectins in response to VHSV infection

“…The mRNA level of CD8 was only induced in the early stage in VHSV-infected olive flounders, while caspase 3 expression was high in both the early and later stages in the kidneys; these results are consistent with previous findings (Avunje et al, 2012). To investigate whether olive flounder lectins were involved in the response to VHSV challenge, quantitative real-time PCR was performed to detect the lectin mRNA levels in the kidneys, spleen, liver and gills, which showed a close relationship with the immune response.…”

“…In adaptive immunity, lectins function as regulators by recognizing bacterial or viral pathogens on DCs, which involves cytokine signal transduction, lymphocyte maturation and polarization against the invading pathogens (den Dunnen et al, 2010).…”

Behavioural fever is a synergic signal amplifying the innate immune response

“…Fish held at constant temperatures provided conditions that were permissive for viral replication and as the temperature decreased viral replication and infection increased. The effect of lower temperatures on viral replication in fish has been suggested to be due to a inhibition of the immune response although at higher temperatures the immune response is considered to be more effective in viral clearance [36,37]. In our model, it is likely that the combination of both factors, optimization of thermal preference to increase the efficiency of the immune response, act in synergy to increase the efficacy of the anti-viral response.…”