Function of CD163 fragments in porcine reproductive and respiratory syndrome virus infection.

Monocyte/macrophage scavenger receptor CD163 plays an important role in porcine reproductive and respiratory syndrome virus (PRRSV) infection. To identify the domains of CD163 involved in PRRSV infection, CD163 fragments P1 (1-798 bp), P2 (790-2046 bp), P3 (2023-3345 bp), Y-P1 (160-798 bp), Y-P2 (790-2046 bp) and Y-P3 (2143-3084 bp) were expressed by eukaryotic and prokaryotic expression systems, respectively. Infection experiments revealed that non-permissive BHK-21 cells transfected with pCD163 could be infected by PRRSV. However, cells with truncated CD163 (P1, P2, or P3) were not susceptible to PRRSV. Meanwhile, Y-P1, Y-P2, and Y-P3 were expressed in E. coli and antisera to these peptides were prepared in mice. A virus blocking test showed that Y-P2 protein and anti-Y-P2 mouse serum could block PRRSV infection in a dose-dependent manner, while Y-P3 protein could improve virus infection.