title: Tick sialostatins L and L2 differentially influence dendritic cell responses to Borrelia spirochetes.
abstract: BACKGROUND
  Transmission of pathogens by ticks is greatly supported by tick saliva released during feeding. Dendritic cells (DC) act as immunological sentinels and interconnect the innate and adaptive immune system. They control polarization of the immune response towards Th1 or Th2 phenotype. We investigated whether salivary cystatins from the hard tick Ixodes scapularis, sialostatin L (Sialo L) and sialostatin L2 (Sialo L2), influence mouse dendritic cells exposed to Borrelia burgdorferi and relevant Toll-like receptor ligands.
  
  
  METHODS
  DCs derived from bone-marrow by GM-CSF or Flt-3 ligand, were activated with Borrelia spirochetes or TLR ligands in the presence of 3 μM Sialo L and 3 μM Sialo L2. Produced chemokines and IFN-β were measured by ELISA test. The activation of signalling pathways was tested by western blotting using specific antibodies. The maturation of DC was determined by measuring the surface expression of CD86 by flow cytometry.
  
  
  RESULTS
  We determined the effect of cystatins on the production of chemokines in Borrelia-infected bone-marrow derived DC. The production of MIP-1α was severely suppressed by both cystatins, while IP-10 was selectively inhibited only by Sialo L2. As TLR-2 is a major receptor activated by Borrelia spirochetes, we tested whether cystatins influence signalling pathways activated by TLR-2 ligand, lipoteichoic acid (LTA). Sialo L2 and weakly Sialo L attenuated the extracellular matrix-regulated kinase (Erk1/2) pathway. The activation of phosphatidylinositol-3 kinase (PI3K)/Akt pathway and nuclear factor-κB (NF-κB) was decreased only by Sialo L2. In response to Borrelia burgdorferi, the activation of Erk1/2 was impaired by Sialo L2. Production of IFN-β was analysed in plasmacytoid DC exposed to Borrelia, TLR-7, and TLR-9 ligands. Sialo L, in contrast to Sialo L2, decreased the production of IFN-β in pDC and also impaired the maturation of these cells.
  
  
  CONCLUSIONS
  This study shows that DC responses to Borrelia spirochetes are affected by tick cystatins. Sialo L influences the maturation of DC thus having impact on adaptive immune response. Sialo L2 affects the production of chemokines potentially engaged in the development of inflammatory response. The impact of cystatins on Borrelia growth in vivo is discussed.
authors.affiliation: Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-37005, České Budějovice, Czech Republic. lieskovs@paru.cas.cz.|Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, CZ-37005, České Budějovice, Czech Republic. lieskovs@paru.cas.cz.
authors.forename: Jaroslava
authors.initials: J
authors.lastname: Lieskovská
authors.affiliation: Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-37005, České Budějovice, Czech Republic. yana.palenikova@seznam.cz.|Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, CZ-37005, České Budějovice, Czech Republic. yana.palenikova@seznam.cz.
authors.forename: Jana
authors.initials: J
authors.lastname: Páleníková
authors.affiliation: Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-37005, České Budějovice, Czech Republic. helca@paru.cas.cz.|Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, CZ-37005, České Budějovice, Czech Republic. helca@paru.cas.cz.
authors.forename: Helena
authors.initials: H
authors.lastname: Langhansová
authors.affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12735 Twinbrook Parkway, Rockville, MD, 20852, USA. andrezza.campos-chagas@nih.gov.
authors.forename: Andrezza
authors.initials: A
authors.lastname: Campos Chagas
authors.affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12735 Twinbrook Parkway, Rockville, MD, 20852, USA. ecalvo@niaid.nih.gov.
authors.forename: Eric
authors.initials: E
authors.lastname: Calvo
authors.affiliation: Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, CZ-37005, České Budějovice, Czech Republic. mich_kotsyfakis@yahoo.com.
authors.forename: Michalis
authors.initials: M
authors.lastname: Kotsyfakis
authors.affiliation: Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-37005, České Budějovice, Czech Republic. jan@paru.cas.cz.|Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, CZ-37005, České Budějovice, Czech Republic. jan@paru.cas.cz.
authors.forename: Jan
authors.initials: J
authors.lastname: Kopecký
mesh_terms: D000818:Animals; D025065:Borrelia burgdorferi / Q000276:immunology*; D015891:Cystatins / Q000494:pharmacology*; D003713:Dendritic Cells / Q000187:drug effects* / Q000502:physiology; D005260:Female; D018884:Ixodes / Q000502:physiology*; D008070:Lipopolysaccharides; D051379:Mice; D008810:Mice, Inbred C57BL; D012463:Saliva / Q000737:chemistry; D015398:Signal Transduction / Q000502:physiology; D013682:Teichoic Acids
chemical_list: D015891:Cystatins; D008070:Lipopolysaccharides; D013682:Teichoic Acids; C515505:sialostatin L, Ixodes scapularis; C009900:lipoteichoic acid