The organ distribution of PRRSV-infected cells in gnotobiotic piglets at 21 days after infection with PRRSV isolate VR-2332 was examined by in situ hybridization. Cells that expressed PRRSV RNA were identified in all tissues examined, including organs not usually characterized as sites of PRRSV infection. PRRSV-infected cells frequently appeared in clusters and were not always associated with microscopic lesions. The expression of PRRSV RNA co-localized with a macrophage monoclonal antibody, MAC-387, in lymph nodes. Some, but not all infected cells stained with MAC-387. The wide distribution of PRRSV-infected cells and co-localization with MAC-387 staining is consistent with the macrophage-tropism of PRRSV and is similar to observations made during persistent infection with other arteriviruses.
Bibliographical noteFunding Information:
We thank Jan Shirers for the MAC-387 immunohistochemistry. This work was supported by the USDA National Research Initiative for Competitive Grants Program Grant # 950224, National Science Foundation Grant # OSR-9108773, and by the South Dakota Future Fund.
- Gnotobiotic pigs
- Porcine reproductive
- Respiratory syndrome