Induction of innate immune responses in pigs infected with H-PRRSV. PAMPs in H-PRRSV viral proteins and nucleic acids are recognized by PRRs that include TLRs (A), cell surface and cytoplasmic PRRs (B), Fc and other receptors (C). After binding to H-PRRSV viral PAMPs, PRRs initiate intracellular signaling cascades that activate transcription factors including IRFs (D) and STATs (F), which in turn induce the expression of IFNγ but not SPIIFNs (E), ISGs (G), pro-inflammatory cytokines and receptors (J), chemokines and receptors (K). Simultaneously, H-PRRSV infection activated complement proteins (I), selectin ligands, adhesion molecules and integrins (H). These recruit immune cells to sites of infection, resulting in severe inflammation and tissue damage. Figure 1H-K represent the heat maps of those DE genes selected. Genes shown in red were up-regulated and those shown in green were down-regulated in infected pigs relative to C pigs (See Additional file 2 for full gene names).