The identification of C-type lectin (Group V) natural killer (NK) cell receptors in bony fish has remained elusive. Analyses of the Fugu rubripes genome database failed to identify Group V C-type lectin domains (Zelensky and Gready, BMC Genomics 5:51, 2004) suggesting that bony fish, in general, may lack such receptors. Numerous Group II C-type lectin receptors, which are structurally similar to Group V (NK) receptors, have been characterized in bony fish. By searching the zebrafish genome database we have identified a multi-gene family of Group II immune-related, lectin-like receptors (illrs) whose members possess inhibiting and/or activating signaling motifs typical of Group V NK receptors. Illr genes are differentially expressed in the myeloid and lymphoid lineages, suggesting that they may play important roles in the immune functions of multiple hematopoietic cell lineages.
"To date, many fish CLR genes have been sequenced, such as a mannose receptor (MR) gene in seabream (Sparus aurata L.)  and grass carp (Ctenopharyngodon idella) , natural killer cell CLRs in Paralabidochromis chilotes and Nile tilapia (Oreochromis niloticus) , CLR-like protein A, B, and C genes in Atlantic salmon (Salmo salar) , immune-related, lectin-like receptor genes gene in zebrafish (Danio rerio)  , and a CLR-like protein gene in ayu (Plecoglossus altivelis) . Fish CLRs have been reported to be involved in pathogen-associated molecular patterns (PAMPs) recognition, phagocytosis and clearance of bacteria by phagocytic cells [5e11]. "
"A putative homolog for DC-SIGN has recently been proposed and is upregulated in immune-related tissues following infection by Aeromonas anguillarum . Finally, putative homologs for the mammalian C-type lectin NK cell receptors have been identified in zebrafish and are differentially expressed on cells from the myeloid and lymphoid lineages . "
[Show abstract][Hide abstract] ABSTRACT: The zebrafish has proven itself as an excellent model to study vertebrate innate immunity. It presents us with possibilities for in vivo imaging of host-pathogen interactions which are unparalleled in mammalian model systems. In addition, its suitability for genetic approaches is providing new insights on the mechanisms underlying the innate immune response. Here, we review the pattern recognition receptors that identify invading microbes, as well as the innate immune effector mechanisms that they activate in zebrafish embryos. We compare the current knowledge about these processes in mammalian models and zebrafish and discuss recent studies using zebrafish infection models that have advanced our general understanding of the innate immune system. Furthermore, we use transcriptome analysis of zebrafish infected with E. tarda, S. typhimurium, and M. marinum to visualize the gene expression profiles resulting from these infections. Our data illustrate that the two acute disease-causing pathogens, E. tarda and S. typhimurium, elicit a highly similar proinflammatory gene induction profile, while the chronic disease-causing pathogen, M. marinum, induces a weaker and delayed innate immune response.
Advances in Hematology 07/2012; 2012(7):159807. DOI:10.1155/2012/159807
"In addition to these considerations, the genomes of two species of bony fish, medaka and zebrafish, have been sufficiently resolved and adequately annotated to make possible the consideration of other gene families in the context of what we understand to be the general features of multigene families encoding the polymorphic NK receptors seen in higher vertebrates. Specifically, no compelling evidence exists for sequence orthologs of either KIRs or class V C-type lectin-related receptors (Zelensky and Gready, 2004; Panagos et al., 2008), members of which constitute MHC I receptors on human and mouse NK cells, respectively. "
[Show abstract][Hide abstract] ABSTRACT: Novel immune-type receptors (NITRs) comprise an exceptionally large, diversified family of activating and inhibitory receptors that has been identified in bony fish. Here, we characterized the structure of an activating NITR that is expressed by a cytotoxic natural killer (NK)-like cell line and that specifically binds an allogeneic B cell target. A single amino acid residue within the NITR immunoglobulin variable (V)-type domain accounts for specificity of the interaction. Structures solved by X-ray crystallography revealed that the V-type domains of NITRs form homodimers resembling rearranging antigen-binding receptor heterodimers. CDR1 elements of both subunits of NITR dimers form ligand-binding surfaces that determine specificity for the nonself target. In the evolution of immune function, it appears that a specific NK type of innate recognition may be mediated by a complex germline multigene family of V structures resembling those that are somatically diversified in adaptive immunological responses.
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.