title: The bioactivity of teleost IL-6: IL-6 protein in orange-spotted grouper (Epinephelus coioides) induces Th2 cell differentiation pathway and antibody production.
abstract: Interleukin 6 (IL-6) is a protein secreted by T cells and macrophages and plays an important role in immune response. IL-6 regulates the proliferation and differentiation of T cells, and elicits immunoglobulin production in B cells. In this study, the cDNA il-6 (gil-6) sequence of the orange spotted grouper (Epinephelus coioides) was obtained. The deduced IL-6 (gIL-6) protein comprised 223 amino acids, the sequence shared approximately 30% similarity with mammalian IL-6, and between 47% and 69% similarity with other available teleost IL-6. The protein comprises the signal peptide, the IL-6 family signature, and conserved amino acid residues found in IL-6 sequences of other teleost. In order to understand the bioactivity and influence of gIL-6 on humoral immune response, recombinant gIL-6 (rgIL-6) synthesized by prokaryotes was injected into orange spotted groupers, and the immune-related gene expression at various times in various organs was observed. Our results revealed that the Th1 specific transcription factor t-bet was down-regulated and Th2 specific transcription factors gata3, and c-maf were up-regulated in immune organs, following IL-6 stimulation. Additionally, higher levels of igm mRNA and translated protein were detected in rgIL-6 stimulated fish. These results indicate that IL-6 in groupers regulates the differentiation of naїve T helper cells into Th2 cells and elicits the production of antibodies.
authors.affiliation: Biotechnology and Institute of Biotechnology, National Cheng Kung University, Tainan 701, Taiwan, ROC.
authors.forename: Hsin-Hung
authors.initials: HH
authors.lastname: Chen
authors.forename: Han-Tso
authors.initials: HT
authors.lastname: Lin
authors.forename: Yi-Fan
authors.initials: YF
authors.lastname: Foung
authors.forename: John
authors.initials: J
authors.lastname: Han-You Lin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000917:Antibody Formation; D001483:Base Sequence; D001492:Bass / Q000276:immunology*; D002454:Cell Differentiation; D003001:Cloning, Molecular; D029941:Fish Proteins / Q000276:immunology*; D015850:Interleukin-6 / Q000276:immunology*; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D018418:Th2 Cells / Q000166:cytology* / Q000276:immunology
chemical_list: D029941:Fish Proteins; D015850:Interleukin-6