Porcine IFI30 inhibits PRRSV proliferation and host cell apoptosis in vitro

Interferon-gamma-inducible protein 30 (IFI30) is an IFN-γ-inducible protein that is involved in MHC class II-restricted antigen processing and MHC class I-restricted cross-presentation pathways of adaptive immunity. The present study aimed to investigate the effects of porcine IFI30 expression on PRRSV proliferation in host cells. MARC-145 cells and pig Sertoli (ST) cells were infected with PRRSV after transfection with porcine IFI30 expression vectors and an empty vector. PRRSV copy numbers were analyzed by absolute real-time quantitative PCR, and the results showed that porcine IFI30 expression could significantly inhibit PRRSV transcription. Western blot analysis also determined that IFI30 expression could reduce the production of PRRSV M protein. Flow cytometric analysis indicated that the apoptosis of MARC-145 cells, which are non-porcine but highly permissive to PRRSV cells, was significantly decreased in the IFI30 expression group. In porcine ST cells, apoptosis was significantly increased in IFI30 knockdown cells but not in IFI30-overexpressing cells (**p < 0.01). In conclusion, porcine IFI30 expression may inhibit PRRSV proliferation and host cell apoptosis in vitro.