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Ixodes ricinus tick salivary gland extract inhibits IL‐10 secretion and CD69 expression by mitogen‐stimulated murine splenocytes and induces hyporesponsiveness in B lymphocytes
Author(s) -
Hannier Sigrid,
Liversidge Janet,
Sternberg Jerry M.,
Bowman Alan S.
Publication year - 2003
Publication title -
parasite immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 75
eISSN - 1365-3024
pISSN - 0141-9838
DOI - 10.1046/j.1365-3024.2003.00605.x
Subject(s) - splenocyte , biology , concanavalin a , lipopolysaccharide , saliva , immunology , cd69 , salivary gland , b cell , t cell , microbiology and biotechnology , mapk/erk pathway , immune system , antibody , il 2 receptor , signal transduction , in vitro , biochemistry
SUMMARY Tick saliva contains immunosuppressive factors allowing this blood‐feeding ectoparasite to remain on hosts and enhancing pathogen transmission. In this study, we examined the modulation of mitogen‐induced activation of naive murine splenocytes by the saliva and salivary gland extract (SGE) of I. ricinus ticks. We found that saliva‐specific factors reduced IL‐10 production by both concanavalin A (ConA) and lipopolysaccharide (LPS) stimulated splenocytes. The LPS‐induced IL‐10 production is 10 times more sensitive to SGE than the ConA‐induced IL‐10 production. Flow cytometric analysis determined that SGE particularly inhibited B (B220 + ) cell IL‐10 production in mitogen‐stimulated splenocyte preparations. Moreover, SGE reduced the early activation marker CD69 expression on ConA‐activated T cells and also on B cells in presence of ConA or LPS. Annexin V and Via‐probe staining demonstrated that SGE did not increase cell death in activated splenocytes and slightly decreased apoptosis in B lymphocytes. By employing assays with isolated B cells, we further showed that SGE had a direct effect on B cells and inhibited LPS‐induced B cell proliferation. Taken together, our results indicate that salivary immunomodulators induce hyporesponsiveness to mitogen in both T and B cells, and that a direct B‐cell inhibitory activity is present in tick saliva.