title: SmCCL19, a CC chemokine of turbot Scophthalmus maximus, induces leukocyte trafficking and promotes anti-viral and anti-bacterial defense.
abstract: Chemokines are classified into several different subfamilies, of which CC chemokines constitute the largest subfamily in teleost. The prominent structural characteristic of CC chemokines is the presence of an Asp-Cys-Cys-Leu (DCCL) motif. To date, cDNA sequences of several CC chemokines have been identified in turbot (Scophthalmus maximus), however, the activity and function of these putative chemokines remain unknown. In this study, we examined the biological effect of the turbot CC chemokine SmCCL19, which has been previously reported as KC70 and shown to be regulated in expression by bacterial infection. To facilitate functional analysis, recombinant SmCCL19 (rSmCCL19) and a mutant form of SmCCL19, SmCCL19M, that bears serine substitutions at the two cysteine residues of the DCCL motif were purified from Escherichia coli. Chemotactic analysis showed that rSmCCL19 induced migration of head kidney leukocytes in a dose-dependent manner, whereas rSmCCL19M caused no apparent cellular migration. To examine the in vivo effect of rSmCCL19, turbot were administered with rSmCCL19 or rSmCCL19M before being inoculated with viral and bacterial pathogens. Subsequent tissue infection analysis showed that the viral and bacterial loads in rSmCCL19-adminsitered fish were significantly reduced, whereas the pathogen loads in rSmCCL19M-adminsitered fish were largely comparable to those in the control fish. Consistent with these observations, significant inductions of immune relevant genes were observed in rSmCCL19-adminsitered fish but not in rSmCCL19M-adminsitered fish. Taken together, these results indicate that SmCCL19 recruits leukocytes and augments host immune defense in a manner that depends on the conserved DCCL motif.
authors.affiliation: Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Chen
authors.forename: Yong-hua
authors.initials: YH
authors.lastname: Hu
authors.forename: Zhi-zhong
authors.initials: ZZ
authors.lastname: Xiao
authors.forename: Li
authors.initials: L
authors.lastname: Sun
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D058491:Bacterial Load / Q000276:immunology; D002465:Cell Movement / Q000276:immunology*; D054415:Chemokine CCL19 / Q000235:genetics / Q000276:immunology*; D002633:Chemotaxis / Q000276:immunology; D017931:DNA Primers / Q000235:genetics; D020609:Edwardsiella tarda / Q000276:immunology; D004926:Escherichia coli; D005412:Flatfishes / Q000276:immunology* / Q000382:microbiology / Q000821:virology; D005786:Gene Expression Regulation / Q000276:immunology*; D007497:Iridoviridae / Q000276:immunology; D007962:Leukocytes / Q000276:immunology*; D010957:Plasmids / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000276:immunology; D019562:Viral Load / Q000276:immunology
chemical_list: D054415:Chemokine CCL19; D017931:DNA Primers; D011994:Recombinant Proteins
keywords: Chemokine; Chemotaxis; Immune defense; Scophthalmus maximus