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Successive tick infestations selectively promote a T‐helper 2 cytokine profile in mice
Author(s) -
Bruno Ferreira,
J.S. Silva
Publication year - 1999
Publication title -
immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.297
H-Index - 133
eISSN - 1365-2567
pISSN - 0019-2805
DOI - 10.1046/j.1365-2567.1999.00683.x
Subject(s) - tick , immunology , biology , cytokine , virology
Several studies have revealed that T lymphocytes and cytokines play a crucial role in determining the outcome of parasitic infections in terms of protective immunity. In this study we found that Rhipicephalus sanguineus tick saliva stimulates transforming growth factor‐β (TGF‐β), and reduces interleukin‐12 (IL‐12) secretion by cells from normal C3H/HeJ mice. Moreover, murine lymph node cells harvested 6 days after the fourth infestation with ticks presented an 82·4% decrease in their proliferative response to concanavalin A (Con A) compared with the response of control cells. In addition, lymph node cells cultured in the presence of Con A showed a T‐helper 2‐type (Th2‐type) cytokine profile, represented by augmented IL‐4 and IL‐10 and TGF‐β. On the other hand, the IL‐2, interferon‐γ (IFN‐γ) and IL‐12 synthesis was significantly inhibited. These results indicate that ticks may modulate the host’s immune response through saliva injection. Consideringthat C3H/HeJ mice develop no protective immunity to R. sanguineus infestation, our results suggest that tick‐induced Th2‐type cytokines and a decreased proliferative response probably lead the host to a susceptible state to both tick and tick‐transmitted pathogens.