Toll like receptor 3 expression patterns in the central nervous system of bovine herpesvirus 5- infected calves

MARIN, M; PÉREZ, S; LEUNDA, M; MOORE, D; ODEÓN, A

Lima

Congreso; X Congreso de la Asociación Latinoamericana de Inmunología (ALAI); 2012

Asociación Latinoamericana de Inmunología (ALAI)

  Bovine herpesvirus 5 (BoHV-5) is the causal agent of necrotizing non-suppurative meningoencephalitis in cattle. In humans, a deficiency of Toll like receptor 3 (TLR3) in the central nervous system (CNS) has been associated with the development of herpes simplex virus encephalitis. The aim of this study was to determine the relative expression of TLR3 in the 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 slaughtered during the peak of acute infection. ,Thirteen calves were inoculated with a low titer dose to induce establishment of latency. Two of them were sacrificed 2 months post-inoculation while the remaining calves were treated with dexamethasone prior to slaughter to stimulate reactivation. Uninfected calves were used as control group. Total RNA from several areas of the frontal cortex and trigeminal ganglia of calves was isolated using Trizol, digested with DNase I and cDNA was synthesized from 1 µg of RNA. Real time RT-PCR reactions contained 800 nM primers, 200 nM probe, 1x PCR Mastermix (TaqMan Universal PCR Mastermix, Applied Biosystems) and 1,5 µl of cDNA. Quantification of TLR mRNA levels and statistical analysis were performed by the Relative Expression Software Tool. TLR3 expression was detected  in uninfected calves. Up-regulation of TLR3 during acute infection and viral reactivation was observed in some areas of frontal cortex. Statistically significant differences were not detected (p>0.05) in TLR3 expression levels in CNS from latently infected calves and in trigeminal ganglia at any stage of infection in neither case. This work is the first report associating TLR3 exression levels to bovine herpesviral infection. In-depth descriptions of the protective mechanisms of TLR3 will greatly contribute to its clinical application. Our findings also contribute to the understanding and knowledge of BoHV pathogenesis.