Molecular and Functional Analyses of the Primordial Costimulatory Molecule CD80/86 and Its Receptors CD28 and CD152 (CTLA-4) in a Teleost Fish

Abstract

The moderate activation of T cells in mammals requires the costimulatory molecules, CD80 and CD86, on antigen-presenting cells to interact with their respective T cell receptors, CD28 and CD152 (CTLA-4), to promote costimulatory signals. In contrast, teleost fish (except salmonids) only possess CD80/86 as their sole primordial costimulatory molecule. However, the mechanism, which underlies the interaction between CD80/86 and its receptors CD28 and CD152 still requires elucidation. In this study, we cloned and identified the CD80/86, CD28, and CD152 genes of the grass carp (Ctenopharyngodon idella). The mRNA expression analysis showed that CD80/86, CD28, and CD152 were constitutively expressed in various tissues. Further analysis revealed that CD80/86 was highly expressed in IgM+ B cells. Conversely, CD28 and CD152 were highly expressed in CD4+ and CD8+ T cells. Subcellular localization illustrated that CD80/86, CD28, and CD152 are all located on the cell membrane. A yeast two-hybrid assay exhibited that CD80/86 can bind with both CD28 and CD152. In vivo assay showed that the expression of CD80/86 was rapidly upregulated in Aeromonas hydrophila infected fish compared to the control fish. However, the expression of CD28 and CD152 presented the inverse trend, suggesting that teleost fish may regulate T cell activation through the differential expression of CD28 and CD152. Importantly, we discovered that T cells were more likely to be activated by A. hydrophila after CD152 was blocked by anti-CD152 antibodies. This suggests that the teleost CD152 is an inhibitory receptor of T cell activation, which is similar to the mammalian CD152. Overall, this study begins to define the interaction feature between primordial CD80/86 and its receptors CD28 and CD152 in teleost fish, alongside providing a cross-species understanding of the evolution of the costimulatory signals throughout vertebrates.

Comparative study on antibacterial characteristics of the multiple liver expressed antimicrobial peptides (LEAPs) in teleost fish

“…To detect the immune responses of LEAPs during infection, rainbow trout and grass carp were intraperitoneally injected with 100 µL Aeromonas salmonicida BG1 ( 29 ) suspension culture (1×10 7 CFU/mL) and 200 µL Aeromonas hydrophila XS91-4-1 ( 30 ) suspension culture (8×10 6 CFU/mL) respectively, while the control fish were intraperitoneally injected with PBS instead after anesthetized with MS222 (1:10000). At 12 h, 1 d, 3 d, 5 d, and 7 d post-injection, the liver and gut of four individuals were sampled from each group.…”

Full T-cell activation and function in teleosts require collaboration of first and co-stimulatory signals

“…The binding of the key co-stimulatory receptor CD28 to the B7 family molecules CD80/CD86 generates co-stimulatory signals that promote T-cell activation, proliferation, survival, and cytokine secretion ( Esensten et al, 2016 ; June et al, 1990 ; Tavano et al, 2006 ). Positive stimulatory effects of CD28 molecules have been reported in several teleost species, including rainbow trout, grass carp, and half-smooth tongue soles ( Hu et al, 2012 ; Lu et al, 2022 ; Zhang et al, 2009 ). For instance, the cytoplasmic tail of trout CD28 mediates ERK phosphorylation, and the chimeric receptor formed by the fusion of the extracellular structure of human CD28 with the cytoplasmic tail of rainbow trout CD28 promotes TCR-induced IL-2 production in human T-cell lines, indicating that trout CD28 is indeed a positive co-stimulatory factor ( Bernard et al, 2006 ).…”

Costimulatory Molecules CD80/86 Trigger Non-Specific Cytotoxic Cell of Nile tilapia (Oreochromis niloticus) to Kill CIK Cells

“…Besides, some studies have indicated that NK cells may be triggered by costimulatory molecules, such as CD86 or molecules that can interact with receptors on NK cells other than CD28 or CTLA-4, and regulated NK cell-mediated cytotoxicity in murine and humans [12,13]. To date, as B7 orthologs, many CD80/86 have been discovered in teleost species, including Nile tilapia (Oreochromis niloticus), rainbow trout (Oncorhynchus mykiss), Atlantic salmon (Salmo salar), zebrafish (Danio rerio), puffer fish (Takifugu rubripes) and grouper (Epinephelus coioides) [14][15][16][17][18]. Meanwhile, CD80/86 could modulate the IL-2 expression of the T-cell effector molecule in rainbow trout [14], and CD80/86 could directly interact with On-CD28 in Nile tilapia [15].…”