Vesicular stomatitis virus nucleocapsid protein production in cells treated with selected fast protein liquid chromatography fractions of tick salivary gland extracts.

A salivary gland extract (SGE) prepared from 5-days-fed Dermacentor reticulatus female ticks was fractionated by fast protein liquid chromatography (FPLC). The effect of three FPLC fractions selected on the basis of anti-interleukin 8 (anti-IL-8) activity on vesicular stomatitis virus (VSV) nucleocapsid (N) protein formation in mouse L-cells was determined. Infected 14C-labeled cells treated with the FPLC fractions were analyzed by two-dimensional (2D) electrophoresis. The yields of VSV N protein were evaluated by Imagemaster software analysis. Most noticeable was an increase in the N protein production after treatment with the fraction 39 corresponding to the major peak of the anti-IL-8 activity. The nature of the substance in SGE that was responsible for this effect remains unclear

Effect of fast protein liquid chromatography fractionated salivary gland extracts from different ixodid tick species on interleukin-8 binding to its cell receptors.

Interleukin-8 plays a critical role in inflammatory processes. Hence generation of molecules with anti-IL-8 activity is likely to be important for successful feeding and for survival of the ticks. Anti-IL-8 activity was studied in saliva of three ixodid tick species--Dermacentor reticulatus (Fabricius, 1794), Rhipicephalus appendiculatus Neumann, 1901, and Amblyomma variegatum (Fabricius, 1794). The greatest activity was shown in saliva prepared from D. reticulatus. The activity was attributed to tick salivary gland molecules that bind to IL-8, preventing binding of the chemokine to its specific receptor, rather than to occupation of the IL-8 cell receptor by the tick molecules. The distribution of anti-IL-8 activity in fast protein liquid chromatography (FPLC) fractions of salivary gland extracts (SGE) derived from adult female D. reticulatus, R. appendiculatus and A. variegatum was compared directly by both ELISA and receptor-binding inhibition assays. The correspondence in results with fractions of SGE from ELISA is consistent with detection of tick molecules that inhibit IL-8 binding to its receptor. As IL-8 is an important chemoattractant and activator of neutrophils, the presence of an anti-IL-8 activity in tick saliva indicates that neutrophils play an important role in the host response to parasitism by ticks

Manipulation of host cytokine network by ticks: a potential gateway for pathogen transmission

Ticks are obligatory blood-feeding arthropods that secrete various immunomodulatory molecules to antagonize host inflammatory and immune responses. Cytokines play an important role in regulating these responses. We investigated the extent to which ticks interact with the sophisticated cytokine network by comparing the effect of salivary gland extracts (SGE) of 3 ixodid tick species, Dermacentor reticulatus, Amblyomma variegatum and Ixodes ricinus, all of which are important vectors of tick-borne pathogens. Using specific ELISAs, anti-cytokine activity was demonstrated with 7 cytokines: IL-8, MCP-1, MIP-1α, RANTES, eotaxin, IL-2 and IL-4. The results varied between species, and between adult males and females of the same species. Relatively high activity levels were detected in saliva of female D. reticulatus, confirming that the observed anti-cytokine activities are an integral part of tick saliva secreted into the host. Results with fractionated SGE indicated that from 2 to 6 putative cytokine binding molecules are produced, depending on species and sex. Binding ability of SGE molecules was verified by cross-linking with radio-isotope labelled MIP-1α. By targeting different cytokines, ixodid ticks can manipulate the cytokine network, which will greatly facilitate blood-feeding and provide a gateway for tick-borne pathogens that helps explain why ticks are such efficient and effective disease vectors