Cross-Species Genome-Wide Analysis Reveals Molecular and Functional Diversity of the Unconventional Interferon-? Subtype

Shields, Lauren E.; Jennings, Jordan; Liu, Qinfang; Lee, Jinhwa; Ma, Wenjun; Blecha, Frank; Miller, Laura C.; Sang, Yongming

Our previous expression analysis of porcine type I IFNs in normal intestine, lymph nodes, and lung revealed that epithelial and constitutive expression of unconventional IFNs (particularly IFN-ε, -κ, -δ, and -ω) in contrast to IFN-α subtype that is prone to an inductive expression during antiviral responses (9, 13). Among IFN-ω subtype, IFN-ω1, -ω2, and -ω3 were expressed higher than IFN-ω4 and -ω5 ( Figure 5A) . In response to the viral infection, we demonstrated that PRRSV-infection induced higher expression (5-10-fold than the control) of multiple IFN subtypes/genes in the lungs from adult sows that had been infected for 14 days. However, the induced expression of IFNs was much weaker (<5-fold) and even suppressed by the PRRSV infection in the fetus from the PRRSV-infected sows and especially unresponsive in the alveolar macrophages infected for 6 h in vitro ( Figure 5B) . Collectively, these findings show that innate immune IFN expression is not restricted to antiviral responses but is extensively involved in immune homeostatic regulation in epithelial mucosa, where inflammation is restricted for normal physiological functions (9, 13, (30) (31) (32) (33) .