Microarray analysis of tick-infested skin in resistant andsusceptible cattle confirms the role of inflammatorypathways in immune activation and larval rejection

Abstract

tTick bites promote activation of an inflammatory process that is influenced by bovinegenetic composition and its history of previous exposure. Taurine and indicine breeds areknown to differ on its immune response development against Rhipicephalus microplus.Nevertheless, further investigation about the complex molecular pathways involved inthe development of immune response to tick infestation in cattle presenting the samegenetic background is mandatory. The aim of this work was to access the early immuneresponse triggered by R. microplus larvae attachment in previously selected resistant andsusceptible animals in a bovine F2 population derived from Gyr (Bos indicus) × Holstein(Bos taurus) crosses. Microarray data analysis of RNA samples from tick infested skin wasused to evaluate the gene expression at 0, 24 and 48 h after R. microplus larvae attachment.Our experimental design allowed us to deeply explore the immune response related toR. microplus infestation avoiding the innate differences between these breeds. The differ-entially expressed genes found reveal networks and pathways that suggest a key role oflipid metabolism in inflammation control and impairment of tick infestation in resistantanimals. Acute phase response also seems to be impaired in susceptible animals. Theseresults provide new insights about early immune response against ticks and raise the pos-sibility of using immunomodulation processes to improve and develop novel tools for tickcontrol