We have isolated and characterized cDNAs and genes for pufferfish, Fugu rubripes, (Fugu) orthologues of mammalian interleukin (IL)-12 subunits (IL-12 p35 and IL-12 p40). The deduced amino acid sequences of the Fugu IL-12 subunits showed homology with mammalian IL-12 subunits (p35: 50.4-58.0% similarity; p40: 51.2-55.4% similarity). Phylogenetic analysis confirmed that Fugu IL-12 p35 and p40 genes cluster with their mammalian counterpart lineages. The genomic organization of each of the Fugu IL-12 subunit genes is similar to that of the corresponding mouse IL-12 subunit genes, although the Fugu genes are very compact due to small intron size. Comparative genomic analysis showed conserved syntenies within the IL-12 p35 and p40 regions between Fugu and human, indicating that the Fugu IL-12 p35 and p40 genes are orthologues for mammalian IL-12 p35 and p40 encoding genes, respectively. Expression of IL-12 p35 mRNA was observed in lymphoid tissues and several non-lymphoid tissues, while expression of IL-12 p40 mRNA was constitutive and nearly ubiquitous. In the spleen and head kidney, expression of IL-12 p35 was induced by polyriboinosinic polyribocytidylic acid [poly(I:C)] and not by lipopolysaccharide (LPS), while expression of IL-12 p40 was constitutive and unresponsive to both poly(I:C) and LPS. These results indicate that IL-12 levels are regulated by production of IL-12 p35 mRNA and suggest that IL-12 in fish may be involved in antiviral defense. This is the first report of the identification and characterization of IL-12 subunit cDNAs and genes in a non-mammalian vertebrate.
"In recent times, fish immunerelevant genes have received considerable attention due to their role in improved understanding of both fish immunology and the evolution of immune systems as such . A Th1-type cytokine (IFNg ) was functionally characterized in rainbow trout  for the first time and further identification of IL-12 in fugu  suggested the presence of conserved Th1 immune response in fish. Cloning, characterization and expression analysis of puffer fish IL-4 was the first evidence of Th2 type cytokine in fish  and later on, cloning of IL-10 gene in the Indian major carp, Labeo rohita was also reported . "
[Show abstract][Hide abstract] ABSTRACT: Immune system is fundamental for survival of an organism against invading pathogens and other harmful agents. Cytokines, the signalling proteins that are produced transiently after cell activation and exert pleiotropic effects on cells of the immune system, are important mediators of cell mediated immune response. When expressed in a dysregulated fashion cytokines can underlie either immunodeficient or immunopathologic states. Heat shock proteins (stress proteins, HSPs) are also key proteins, which play important role in immunomodulation, apoptosis and influence the immune responses. Arsenic is a major toxic environmental contaminant and a human carcinogen. Prolonged drinking of arsenic-contaminated water leads to chronic arsenic toxicity (arsenicosis). Arsenic is also immunotoxic and renders the host immunocompromised. Arsenic exposure has been reported to result in growth retardation, gross pathology including skin and eye lesions, ulcerations, cataract development etc. in different fish species The present study was undertaken to investigate the effect of arsenic exposure on the expression of immune genes IFN-γ, IL-4, IL-10, IL-12, complement C3a and HSP genes HSP47, HSP60, HSP70, HSP71, HSP78, and HSP90 in Labeo rohita, an important aquacultured species, as such information is not available on this major carp. Cytokine and HSP gene expression analyses were carried out in kidney and liver tissues, respectively, in arsenic-exposed fishes by RT-PCR and HSPs were analyzed by immunoblotting. It was observed that arsenic has a generalized immune-suppressive effect leading to down regulation of both Th1 and Th2 cytokines; besides, it led to up regulation of the HSP genes indicating arsenic-induced cellular stress. Thus arsenic exposure makes Labeo rohita immunocompromised and could increase its susceptibility to pathogen attacks.
"Despite the considerable recent increase in the elucidation of the cytokine network in lower vertebrates, the fish IL-12 cytokine family remains poorly characterised (Degen et al., 2004; Secombes et al., 2011; Wang and Secombes, 2013). A single p35 gene and up to three p40 paralogues (p40a, p40b and p40c) have been reported in a few fish species (Yoshiura et al., 2003; Huising et al., 2006; Nascimento et al., 2007; Øvergård et al., 2012; Tsai et al., 2014; Wang et al., 2014). Other subunits, including Ebi3 (Secombes et al., 2011; Li et al., 2013), p19 (Holt et al., 2011) and p28 (Wang and Husain, 2013), have also been identified recently in teleost fish. "
[Show abstract][Hide abstract] ABSTRACT: Interleukin (IL)-12 family cytokines are heterodimers of an α-chain (p19, p28 and p35) and a β-chain (p40 and Ebi3), present as IL-12 (p35/p40), IL-23 (p19/p40), IL-27 (p28/Ebi3) and IL-35 (p35/Ebi3), and play key roles in immune responses in mammals. One p35 and up to three p40 genes have been cloned in some fish species. The identification of three active p35 genes, along with three p40 paralogues in salmonids in the current study further expands the repertoire of IL-12, IL-23 and IL-35 molecules in these species. The multiple p35 genes in teleost fish appear to have arisen via whole genome duplications. The different paralogues of the subunits are divergent, and differentially expressed and modulated by PAMPs and proinflammatory cytokines, hinting that distinct isoforms could be produced in response to infection. Therefore, the expanded IL-12 cytokine family may provide an unprecedented level of regulation to fine tune the immune response in fish.
"It is not known if T cells play a role in regulatory functions similar to their role in mammals, although the expression of cytokines such as IFNg, IL-10, IL-17 and TGF-b1 suggests that Th1, Th2, Th17 and T regulatory response types exist [27e33]. Regarding macrophages, it is well established that they are abundant in head kidney, showed phagocytic properties and expresses the machinery of antigen processing and presentation (MHC, TAP, LMP)   and cytokines such as IL-12  . The presence of dendritic cells is disputed; just some morphological evidence indicates that these are antigenpresenting cells in fish [38e42] "
[Show abstract][Hide abstract] ABSTRACT: Alternative splicing is an important mechanism of gene expression control that also produces a large proteome from a limited number of genes. In the immune system of mammals, numerous relevant genes have been found to undergo alternative splicing that contributes to the complexity of immune response. An increasing number of reports have recently indicated that alternative splicing also occurs in other vertebrates, such as fish. In this review we summarize the general features of such molecular events in cytokines and leukocyte co-receptors and their contribution to diversity and regulation of fish leukocytes.
Nizar Jamal Haddad, Adjlane Noureddine, Banan Al-Shagour, Wahida Loucif-Ayad, Mogbel A A El-Niweiri, Eman Anaswah, Wafaa Abu Hammour, Dany El-Obeid, Albaba Imad, Mohamed A Shebl, Abdulhusien Sehen Almaleky, Abdalah Nasher, Nagara Walid, Mohamed Fouad Bergigui, Orlando Yañez, Joachim R de Miranda
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.