Expression of immune-related genes of Nile tilapia Oreochromis niloticus after Gyrodactylus cichlidarum and Cichlidogyrus sclerosus infections demonstrating immunosupression in coinfection

Acting locally - affecting globally: RNA sequencing of gilthead sea bream with a mild Sparicotyle chrysophrii infection reveals effects on apoptosis, immune and hypoxia related genes

“…Fish reaction against monogenean infections has been broached in the last decade using molecular tools. However, most studies have focused on few monogenean genera (all belonging to the Monopisthocotylean clade), mainly Dactylogyrus and Gyrodactylus, and employed targeted approaches (RT-qPCR) to study few or a group of genes (mainly immune-related genes) [19][20][21][22][23][24][25][26][27].…”

“…The general overview could be considered as an inflammatory scenario in the gills, with a clear up-regulation of some pro-inflammatory cytokines, such as ifnγ, IFN-regulated genes and other inflammation markers, and activation of immunoglobulins, complement factors, lymphoid and myeloid response, some lectins and cytotoxic enzymes as perforin-1-like. In most monogenean studies focusing on the regulation of immune genes, il1β, tnfα [19,20,23,[25][26][27]75], ifnγ [25,76], tgfβ [19,20,26,27,75] and some TLRs [22] appeared up-regulated at the local level (gills, skin) in relatively short times after exposure to the parasite (from 4 to 30 days). We also observed a down-regulation of several molecules related to the Il4/13 signalling pathway and down-regulation of mucin 5 in NP gills, which is opposite to what we recently described in Atlantic salmon (Salmo salar) infected with the gill parasite Neoparamoeba perurans [77].…”

“…Unlike in Sparicotyle-GSB interaction, the number of Gyrodactylus parasites tends to decline 20-30 days post-infection, suggesting an adaptive immune mechanism. The first studies showed that macrophage secretion of complement factor 3 (C3) and interleukin 1β (Il1β) induced epithelial hyperplasia and mucus secretion [18], and later on, the picture of the immune response to monogeneans became more complex, and differed depending on the host and the specific parasite studied [19][20][21][22][23][24][25][26][27]. To our knowledge, there is no information about the genes involved in GSB response or comprehensive studies on the fish host response to monogenean infection inferred by massive sequencing.…”

The nature and consequences of co‐infections in tilapia: A review

“…Furthermore, Zhi et al (2018) have evaluated and compared the effects of single parasitic infection with co‐infection between G. cichlidarum and C. sclerosus and the immune response and the expression of immune‐related genes, such as interleukin‐1β (IL‐1β), tumour necrosis factor‐alpha (TNF‐α), transforming growth factor‐beta (TGF‐β), heat‐shock protein 70 (HSP70) and cyclooxygenase‐2 (COX‐2), on the exposed Nile tilapia. These authors demonstrated that the synergistic interaction between the two monogeneans resulted in immunosuppression with significant down‐regulation of the expression of TNF‐α, TGF‐β and COX‐2 in the gills at day 2 after G. cichlidarum infection on the skin.…”

“…This can lead to a subsequent increase in the severity of infection with a higher mortality rate (Eissa et al, 2013). For example, suppression of the localized mucous immunity of Nile tilapia after G. cichlidarum infection may explain an apparent elevation of the fish susceptibility to C. sclerosus infection (Zhi et al, 2018). Similar findings were reported in goldfish, Carassius auratus , infected with Dactylogyrus intermedius that showed down‐regulation of TGF‐β expression and became more susceptible to F. columnare (Zhang et al, 2015).…”