| Porcine reproductive and respiratory syndrome(PRRS), formerly known as “blue ear pig disease†is the most important disease threatening swine industry in the world today. Macrophages are a widespread immune system cells which could polarize to two types: classic activated macrophages(M1) and alternative activation of macrophages(M2) according to the changes of the internal environment. In order to study the interaction between PAMs polarization and infection with PRRSV, we first established a PAMs polarization model in vitro. PAMs was induced by LPS/IFN-γ to M1 subtype of PAMs and IL-4 to M2 subtype of PAMs. Expression of M1 and M2 type Marker were detected by Real-time PCR, semiquantitative PCR and Western blot, the results indrcated that M1-type macrophages were successed by related marks molecules TNF-α, IL-1β, IL-6, IL-12 and M2-type macrophages were successed by related marks molecules Arg-1, IL-10, PPARγ, suggesting that the PAM polarization model was established successfully.To explore the polarization type of PAMs infected with PRRSV, M1 and M2-type PAMs were infected with 500TCID50 HuN4-F5 train of PRRSV respectively. Virus titer was detected in 12, 24, 36 and 48 h after PRRSV infection.The results showed that the virus titer of M1-type PAMs was significantly lower than M0 and M2-type PAMs at the time of 12 to 36 h post infection, but there was no significant difference between M1 and M2 type PAMs at the time of 48 h. Real-time PCR was proformed to detected the expression of cytokines of M1-type PAMs, showing that cytokines like IFN-α, IL-6, TNF-α, IFIT3 and heme oxygenase-1(HO-1) which inhibited the infection of PRRSV were significant increased compared with M0 and M2-type PAMs(P<0.01), This result that inflammatory factors generated by M1-type of PAMs inhibit the infection of PRRSV.In order to explore the polarization types of PAMs after PRRSV infection, M1 and M2 of type Marker were detected. The results showed that M2-type Marker increased at 6h and reached the highest level at 48 h, M1-type Marker without any significant changes, indicating that PAMs polarized mainly towards the M2-type after PRRSV infection.In conclusion, this study describes that PAMs polarization model was established successfully M1-type PAMs inhibited the infection of PRRSV. PAMs were polarized to M2-type macrophages after PRRSV infection.This study will provide new insights into elucidating the relationship between PRRSV and PAMs further. |
