Abstract
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.
Original language | English |
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Pages (from-to) | 27-37 |
Number of pages | 10 |
Journal | Parasite Immunology |
Volume | 25 |
Issue number | 1 |
DOIs | |
Publication status | Published - Jan 2003 |
Keywords
- B lymphocytes
- IL-10
- immunosuppression
- Ixodes ricinus
- salivary glands
- tick
- LYME-DISEASE VECTOR
- BORRELIA-BURGDORFERI
- IN-VITRO
- IFN-GAMMA
- CYTOKINE PRODUCTION
- CELL ACTIVATION
- IMMUNE-RESPONSE
- BALB/C MICE
- SCAPULARIS
- PROTEIN