Two-dimensional liquid chromatography-tandem mass spectrometry coupled with isobaric tags for relative and absolute quantification (iTRAQ) labeling approach revealed first proteome profiles of pulmonary alveolar macrophages infected with porcine circovirus type 2.

Porcine circovirus type 2 (PCV2) has been identified as the essential causal agent of postweaning multisystemic wasting syndrome, which has spread worldwide. Monocyte/macrophage lineage cells are the major target cells of PCV2. To discover cellular protein responses of pulmonary alveolar macrophages (PAMs) to PCV2 infection, two-dimensional liquid chromatography-tandem mass spectrometry coupled with isobaric tags for relative and absolute quantification (iTRAQ) labeling was employed to quantitatively identify the proteins that were differentially expressed in PAMs from the PCV2-infected group compared to the uninfected control group. A total of 145 cellular proteins in PAMs that were significantly altered at different time periods post-infection were identified. These differentially expressed proteins were related to the biological processes of binding, cell structure, signal transduction, cell adhesion, etc., and their interactions. The high number of differentially expressed proteins identified should be very useful to elucidate the mechanism of replication and pathogenesis of PCV2 in the future.