title: Identification and partial characterization of a Salp15 homolog from Ixodes ricinus.
abstract: The immunomodulatory molecule Salp15 is originally described in Ixodes scapularis and has been shown to inhibit CD4 T cell activation. Many Salp15 homologs have been described from Ixodes species, and all were well conserved at C-terminal residues that seem to be essential for the function of the protein. In this study, a gene sequence was amplified from cDNA isolated from engorged female I. ricinus ticks, which was predicted to generate a protein of 12.3 kDa. The protein displayed distinct amino acid differences from previously described I. ricinus Salp15 homologs, with amino acid identity ranging between 46.6% and 93.9%. It was referred to as I. ricinus Salp15-like protein. The protein showed 48.1% sequence identity to I. scapularis Salp15. We analyzed the effect of the recombinant I. ricinus Salp15-like protein on the production of cytokines from human peripheral blood mononuclear cells stimulated with LPS. The recombinant protein exerted no effect on the production of TNF-α and IL-6, but the production of IL-10 was dose-dependently reduced. It can be concluded that I. ricinus Salp15-like protein exerts an immunomodulatory effect on the host. The inhibition of IL-10 production may possibly lead to a retardation of B cell activity.
authors.affiliation: Division of Veterinary Infection Biology and Immunology, Department of Molecular Infection Biology, Research Center Borstel, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.affiliation: Division of Veterinary Infection Biology and Immunology, Department of Molecular Infection Biology, Research Center Borstel, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Renneker
authors.affiliation: Division of Veterinary Infection Biology and Immunology, Department of Molecular Infection Biology, Research Center Borstel, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Beyer
authors.affiliation: Division of Veterinary Infection Biology and Immunology, Department of Molecular Infection Biology, Research Center Borstel, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Kullmann
authors.affiliation: Division of Veterinary Infection Biology and Immunology, Department of Molecular Infection Biology, Research Center Borstel, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Seitzer
authors.affiliation: Division of Veterinary Infection Biology and Immunology, Department of Molecular Infection Biology, Research Center Borstel, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Ahmed
authors.affiliation: Division of Veterinary Infection Biology and Immunology, Department of Molecular Infection Biology, Research Center Borstel, Germany. Electronic address: mbakheit@fz-borstel.de.
authors.forename: M A
authors.initials: MA
authors.lastname: Bakheit
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D005260:Female; D015870:Gene Expression; D006801:Humans; D016753:Interleukin-10 / Q000032:analysis / Q000378:metabolism*; D018884:Ixodes / Q000235:genetics* / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008969:Molecular Sequence Data; D010802:Phylogeny; D011994:Recombinant Proteins; D012471:Salivary Proteins and Peptides / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: C508609:IL10 protein, human; D011994:Recombinant Proteins; D012471:Salivary Proteins and Peptides; D016753:Interleukin-10
keywords: IL-10; IL-6; Ixodes ricinus; Salivary glands; Salp15; TNF-α