Effects of PRRSV on Transcription of IFN-γ and Its Key Signal Molecules

Purpose In order to explore the effect of porcine reproductive and respiratory syndrome virus (PRRSV) on the transcription of IFN-γ and its key signaling molecules IRF3 and IRF7 in porcine alveolar macrophages (PAMs) in vitro.

Method The PAMs were isolated aseptically with lavation from piglet and divided into control group, PRRSV group and cultured in vitro. The PAMs and its culture supernatant were collected respectively at different time points (6, 12, 24, 48 and 60 h) after PRRSV infection. Using ELISA to determine the changes of IFN-γ mass concentrations in the cell culture supernatant, and the mRNA transcription of PRRSV, IFN-γ, IRF3 and IRF7 were analyzed by real-time PCR.

Result There was no significant difference of the mass concentrations of IFN-γ protein between PRRSV group and normal control group. Compared with the control group, IFN-γ mRNA transcription in PRRSV group significantly increased at 24 h and 48 h (P<0.01), decreased after 48 h,IRF3 (P<0.05) andIRF7 (P<0.01) mRNA transcription level significantly reduced at 60 h.

Conclusion The results indicated that the transcription level of IFN-γ mRNA during PRRSV infection with PAMs showed a first inhibition of re-activation after the suppression by regulating IRF3 and IRF7 transcription level to a certain extent.