EIAV replication and induction of infection resistance in eMDM after TLR3 mRNA knockdown. (A) The inhibitory effect of poly I:C on EIAVUK3 replication in eMDM transfected with specific siRNA-TLR3 or control siRNA-C. After transfection with siRNA for 48 h, the cells were stimulated with 0.5 μg/mL poly I:C for 12 h before infection with EIAVUK3. Viral RNA copies were measured with qPCR at 72 hpi. (B) The effect of TLR3 mRNA knockdown on the resistance to subsequent viral infection induced by EIAVFDDV13. eMDM transfected with TLR3-specific or control siRNA were first infected with EIAVFDDV13. The cells were subsequently infected with EIAVUK3 at different times; at 72 h later, the viral RNA copy numbers of EIAVUK3 in the culture medium were measured with qPCR and compared with the EIAVUK3 RNA copy numbers in eMDM that were not initially infected with EIAVFDDV13. *P < 0.05, **P < 0.01.