GDI1 and infection: To evaluate the inhibitory effect of SR717 on the infection of different virulent strains of PRRSV in PAMs, PAMs were inoculated in 6-well plates and cultured for 12 h and pretreated with SR717, and infected with different virulent strains of PRRSV (JXA1, GD-HD, VR2332, and CH-1a) for 36 h.