English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Mammalian interleukin (IL)-2 is a cytokine centrally involved in the differentiation and survival of CD4+ T helper subsets and CD4+ T regulatory cells and in activation of cytotoxic effector lymphocytes. In bony fish,  IL2  orthologs have been identified with an additional divergent  IL2-Like  gene on the same locus present in several fish species. We report here two divergent  IL2  paralogs,  IL2A  and  IL2B , in salmonids that originated from the whole genome duplication event in this fish lineage. The salmonid  IL2  paralogs differ not only in sequence but also in exon sizes. The IL-2 isoforms that are encoded have disparate pI values and may have evolved to preferentially bind specific IL-2 receptors. Rainbow trout  IL2  paralogs are highly expressed in thymus, spleen, gills, kidney and intestine, important tissues/organs in fish T cell development and function. Their expression in peripheral blood leukocytes (PBL) is low constitutively but can be upregulated by the mixed leukocyte reaction, by the T cell mitogen phytohemagglutinin and by signal mimics of T cell activation (phorbol 12-myristate 13-acetate and calcium ionophore). Both trout IL-2 isoforms promoted PBL proliferation and sustained high-level expression of  CD4  and  CD8 , suggesting that trout IL-2 isoforms are T cell growth/survival factors mainly expressed by activated T cells. The recombinant proteins for these two trout  IL2  paralogs have been produced in  E. coli  and possess shared but also distinct bioactivities. IL-2A, but not IL-2B, induced  IL12P35A1  and  CXCR1  expression in PBL. IL-2B had a stronger effect on upregulation of the T helper 1 (Th1) cytokine  interferon-γ  ( IFNγ ) and could sustain  CD8α  and  CD8β  expression levels. Nevertheless, both cytokines upregulated key Th1 ( IFNγ1, IFNγ2, TNFα2  and  IL12 ) and T helper 2 (Th2) cytokines ( IL4/13B1  and  IL4/13B2 ), cytokine and chemokine receptors and the antimicrobial peptide  cathelicidin-1  but had limited effects on T helper 17 cytokines and  TGFβ1  in PBL. They could also enhance PBL phagocytosis. These results suggest, for the first time in fish, that IL-2 isoforms may have an important role in regulating Th1 and Th2 cell development, and innate and adaptive host defenses in fish, and shed light on lineage-specific expansion, evolution, and functional diversification of  IL2  in vertebrates.

frontiers in immunology

Interleukin (IL)-2 Is a Key Regulator of T Helper 1 and T Helper 2 Cytokine Expression in Fish: Functional Characterization of Two Divergent IL2 Paralogs in Salmonids