Received 17 September 2007; accepted 7 October 2007. Available online 22 October 2007.
Ticks are blood-feeding arthropods that secrete immunomodulatory molecules through their saliva to antagonize host inflammatory and immune responses.
As dendritic cells (DCs) play a major role in host immune responses, we studied the effects of Rhipicephalus sanguineus tick saliva on DC migration and function.
Bone marrow-derived immature DCs pre-exposed to tick saliva showed reduced migration towards macrophage inflammatory protein (MIP)-1α, MIP-1β and regulated upon activation, normal T cell expressed and secreted (RANTES) chemokines in a Boyden microchamber assay.
This inhibition was mediated by saliva which significantly reduced the percentage and the average cell-surface expression of CC chemokine receptor CCR5.
In contrast, saliva did not alter migration of DCs towards MIP-3β, not even if the cells were induced for maturation.
Next, we evaluated the effect of tick saliva on the activity of chemokines related to DC migration and showed that tick saliva per se inhibits the chemotactic function of MIP-1α, while it did not affect RANTES, MIP-1β and MIP-3β.
These data suggest that saliva possibly reduces immature DC migration, while mature DC chemotaxis remains unaffected.
In support of this, we have analyzed the percentage of DCs on mice 48 h after intradermal inoculation with saliva and found that the DC turnover in the skin was reduced compared with controls.
Finally, to test the biological activity of the saliva-exposed DCs, we transferred DCs pre-cultured with saliva and loaded with the keyhole limpet haemocyanin (KLH) antigen to mice and measured their capacity to induce specific T cell cytokines.
Data showed that saliva reduced the synthesis of both T helper (Th)1 and Th2 cytokines, suggesting the induction of a non-polarised T cell response.
These findings propose that the inhibition of DCs migratory ability and function may be a relevant mechanism used by ticks to subvert the immune response of the host.
Carlo José F. Oliveiraa, Karen A. Cavassania, Daniela D. Moréa, Gustavo P. Garletc, Julio C. Alibertid, João S. Silvaa and Beatriz R. Ferreiraa, b, , aDepartment of Biochemistry and Immunology, School of Medicine of Ribeirão Preto, University of São Paulo (USP), SP, Brazil bDepartment of Maternal-Child Nursing and Public Health, School of Nursing of Ribeirão Preto, USP, Avenida Bandeirantes 3900, 14040 902 Ribeirão Preto, SP, Brazil cDepartment of Biological Sciences, School of Dentistry of Bauru, USP, SP, Brazil dDivision of Molecular Immunology, Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH, USA
Keywords: Dendritic cells; Saliva; Migration; T cell response; Rhipicephalus sanguineus
Corresponding author. Address: Department of Maternal-Child Nursing and Public Health, School of Nursing of Ribeirão Preto, USP, Avenida Bandeirantes 3900, 14040 902 Ribeirão Preto, SP, Brazil. Tel.: +55 016 3602 3231; fax: +55 016 3602 4590.
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-------------------- Note: I'm NOT a medical professional. The information I share is from my own personal research and experience. Please do not construe anything I share as medical advice, which should only be obtained from a licensed medical practitioner. Posts: 4881 | From Middlesex County, NJ | Registered: Jul 2006
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Frequent Contributor (5K+ posts)
Member # 10397
This is kind of technical but (I think) it supports a post I made
about transmission of Lyme disease through kissing or sexual
contact. It's the initial bite from the tick where other chemicals in
the tick's saliva prevent the detection of the spirochete in the body.
Human to human contact wouldn't have the same effect as tick to
human... I'm supposing here.
Posts: 7772 | From Northeast, again... | Registered: Oct 2006
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