Salivary gland extract from Ixodes ricinus tick polarizes the cytokine profile toward Th2 and suppresses proliferation of T lymphocytes in human PBMC culture.
Tick salivary gland extract (SGE) was previously shown to inhibit murine T cell proliferation. In mice, SGE has an inhibitory effect on Th1 and a stimulatory effect on Th2 cytokine elaboration. In the present study, tick-mediated immunomodulation of human T cell proliferation and cytokine elaboration was analyzed using human peripheral blood mononuclear cells (PBMCs) stimulated with concanavalin A (Con A) or lipopolysaccharide (LPS). Using flow cytometry, tick saliva-induced changes were investigated in human mononuclear cell subpopulations. SGE from Ixodes ricinus dose-dependently inhibited human T cell proliferation. This finding supports the flow cytometry data, showing that the percentage of Con A-activated HLA-DR-CD3+ T lymphocytes and CD4+ CD8+ double-positive T cells decreased after SGE treatment. SGE significantly inhibited the in vitro production of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) secreted by Th1 lymphocytes. In contrast, the elaboration of IL-4, IL-6, and IL-10 secreted by Th2 lymphocytes was significantly stimulated by I. ricinus SGE. Similarly, the production of both IL-1alpha and IL-1beta was significantly stimulated after SGE treatment. These data indicate that the tick-induced immunomodulatory events in humans are similar to those previously described in a murine model.
Kovár
L
L
Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague.
Kopecký
J
J
Ríhová
B
B
D000276:Adjuvants, Immunologic; D000818:Animals; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis*; D006801:Humans; D018884:Ixodes / Q000276:immunology*; D008213:Lymphocyte Activation; D012469:Salivary Glands / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D018418:Th2 Cells / Q000166:cytology / Q000276:immunology*
D000276:Adjuvants, Immunologic; D016207:Cytokines