TOLL LIKE RECEPTOR 3 EXPRESSION PATTERNS IN THE CENTRAL NERVOUS SYSTEM OF BOVINE HERPESVIRUS 5- INFECTED CALVES

MARIN MS; PÉREZ SE; QUINTANA S; LEUNDA MR; PEREYRA SE; ODEÓN AC

Mar del Plata

Encuentro; VII Encuentro Biólogos en Red; 2012

AJIF

Bovine herpesvirus 5 (BoHV-5) is the causal agent of necrotizing non-suppurativemeningoencephalitis in cattle. In humans, a deficiency of Toll like receptor 3 (TLR3) in thecentral nervous system (CNS) has been associated with the development of herpes simplexvirus encephalitis. The aim of this study was to determine the relative expression of TLR3 inthe CNS of calves infected with BoHV-5 during acute infection, latency and viral reactivation.Twelve calves were inoculated with BoHV-5 at doses of high titer and they were slaughteredduring the peak of acute infection. Thirteen calves were inoculated with a low titer dose toinduce establishment of latency. Two of them were sacrificed 2 months post-inoculation whilethe remaining calves were treated with dexamethasone prior to slaughter to stimulatereactivation. Uninfected calves were used as control. The handling and euthanasia of animalswere performed according to the criteria of the Institutional Committee for Care and Use ofExperimental Animals (CICUAE) of INTA. Total RNA from several areas of the frontal cortex andtrigeminal ganglia of calves was isolated by using Trizol, digested with DNase I and cDNA wassynthesized from 1 μg of RNA. Real time RT-PCR was applied for quantification of TLR mRNAlevels. The expression of TRL3 was measured and statistical analysis was performed by usingthe Relative Expression Software Tool. TLR3 expression was detected in uninfected calves.Significant up-regulation of TLR3 during acute infection and viral reactivation was observed insome areas of frontal cortex. Statistically significant differences were not detected in TLR3expression levels in CNS from latently infected calves and in trigeminal ganglia at any stage ofinfection in neither case. This work is the first report associating TLR3 expression levels toherpesviral infection in cattle. In-depth descriptions of the protective mechanisms of TLR3 willgreatly contribute to its clinical application. Our findings also contribute to the understandingand knowledge of BoHV pathogenesis.