Effects of TLR7/8 stimulation on bovine herpesvirus types 1 and 5 replication.

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

Lima

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

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

Studies on the effect of Toll like receptors (TLRs) activation on Bovine Herpesvirus (BoHV) replication have not been reported. To test whether immunological effectors expressed after stimulation of TLRs have an effect on BoHV-1 and 5 replication, PBMC from serum-negative calves were stimulated with Imiquimod, a TLR7/8 agonist, for 6 or 24 h. Supernatants from stimulated PBMC were harvested and added to MDBK cells previously infected with BoHV-1 or BoHV-5 strains for 0, 4, 6 or 24 h (MOI 0.1). After an incubation of 24 h, supernatants were harvested and virus titres were determined by the end-point titration method. Three replicas of each experiment were performed. As negative control, supernatants from non-stimulated PBMC were added to infected MDBK cells. Supernatants obtained after PBMC stimulation demonstrated to have antiviral activity. Stimulation with Imiquimod for 6 and 24 h significantly decreased (p <0.05) extracellular BoHV-1 and 5 yields during the first hours of viral infection. By contrast, treatment at later stages of the viral replication cycle (i.e, 24 h after the initiation of BoHV infection) completely failed to execute a protective effect. The results from this study are the first evidence that timely activation of TLR7/8 signaling is effective in impairing BoHV replication, providing an experimental clue that Imiquimod may be a promising immune-modulator against BoHV infection, which might be applicable for clinical prevention.