Níveis de citocinas em bovinos (Bos indicus) desafiados com o carrapato Boophilus microplus (Cannestrini, 1887)

Abstract

Boophilus microplus tick affects cattle productivity causing economic losses in the order of billions of dollars annually. It is know that tick saliva exert immunomodulatory effects, an evolutionary adaptation to the immune response of the host that can counteract tick feeding. It has been suggested that the outcome of many parasitic infections with regard to resistance or susceptibility is determined by the pattern of response involving Th1 and Th2 cells, which produce specific cytokines that may direct the immune response towards different mechanisms. Limited information is available regarding to the host response to B. microplus tick infestation. In an attempt to improve our knowledge about cattle immune-response to ticks, this work determined the expression levels of cytokines mRNAs in two groups of Nelore (Bos indicus) calves: one control and other challenged by tick infestation. Our results demonstrated a down-regulation of IL-2 (P < 0.03) mRNA levels in challenged animals, while no effect of tick challenge was observed for IL-4, IL-8, IL-12p35, TNF-&#945; and MCP-1. The down regulation of an important Th1 cytokine suggests a tendency towards a Th2 response pattern, which is in agreement with similar studies conducted with other tick-host models.