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Parasit Vectors. 2017 Jul 10;10(1):326. doi: 10.1186/s13071-017-2248-8.

Interaction between saliva's adenosine and tick parasitism: effects on feeding and reproduction.

Author information

1
Institute of Science and Technology, Federal University of São Paulo, UNIFESP, Rua Talim, 330, São José dos Campos, São Paulo, 12231-280, Brazil. elen.anatriello@unifesp.br.
2
Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, UFTM, Praça Manoel Terra, 330, Uberaba, Minas Gerais, 38015-050, Brazil.
3
Department of Maternal and Child and Public Health Nursing, Ribeirão Preto School of Nursing, University of São Paulo, USP, Avenida Bandeirantes, 3900 Ribeirão Preto, São Paulo, 14040-902, Brazil.
4
Department of Biochemistry and Immunology, Ribeirão Preto School of Medicine, University of São Paulo, USP, Avenida Bandeirantes, 3900 Ribeirão Preto, São Paulo, 14049-900, Brazil.

Abstract

BACKGROUND:

It has recently been demonstrated that saliva from Rhipicephalus sanguineus ticks contains adenosine (ADO) and prostaglandin E2 (PGE2), two non-protein molecules that have significant immunomodulatory properties. These molecules can inhibit cytokine production by dendritic cells (DCs), while also reducing the expression of CD40 in these cells. However, more studies are needed for a better understanding of their participation in the feeding of ticks in vivo. This work, therefore, evaluated the importance of ADO during tick infestations. Mice were infested with adult ticks (3 couples/mouse), and their skin was collected at the tick-infested site (3rd and 7th day), and mRNA for receptors of ADO was quantified by real-time PCR.

RESULTS:

Tick infestation increased by four and two times the expression of the A2b and A3v1 receptors on day 3, respectively, while expression of other ADO receptors was unaltered. In addition, we treated mice (n = 10/group) daily with 8-(p-Sulfophenyl)theophylline, 8-pSPT, 20 mg/kg, i.p.), a non-selective antagonist of ADO receptors, and evaluated the performance of ticks during infestations. Female ticks fed on 8-pSPT-treated mice presented a reduction in their engorgement, weight and hatching rates of egg masses, and survival times of larvae compared to the same parameters presented by ticks in the control group. To investigate if these 8-pSPT-treated mice presented altered immune responses, we performed three tick infestations and collected their lymph node cells to determine the percentages and activation state of DCs and cytokine production by lymphocytes by flow cytometry (Cytometric Bead Array technique, CBA). Our data showed that 8-pSPT-treated mice presented an increase in the percentage of DCs as well as of their stimulatory and co-stimulatory molecules (CD40, CD80 and MHCII). Regarding production of T cell cytokines, we observed a significant increase in the levels of IL-2 and a significant decrease in IL-10, IL-17, TNF-α and IFN-γ cytokines.

CONCLUSIONS:

These results suggest that ADO produced by ticks helps them feed and reproduce and that this effect may be due to modulation of host DCs and T cells.

KEYWORDS:

Adenosine; Dendritic cells; Rhipicephalus sanguineus; Saliva; T cells; Ticks

PMID:
28693553
PMCID:
PMC5502490
DOI:
10.1186/s13071-017-2248-8
[Indexed for MEDLINE]
Free PMC Article

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