Figure 4. High levels of CD163 expression determine PRRSV replication.
(A) Three CD163 expression patterns (low, middle and high levels) were isolated using flow cytometry sorting technology. The representative isolated cell clones were designated PAM-Tang-low, PAM-Tang-middle and PAM-Tang-high, respectively. (B) The CD163 expression levels of PAM-Tang-low, PAM-Tang-middle and PAM-Tang-high cells were confirmed by flow cytometry and (C) Western blotting. (D) PAM-Tang, PAM-Tang-low, PAM-Tang-middle and PAM-Tang-high cells showed different susceptibilities to PRRSV infection. All immortalized cells were infected with PRRSV HuN4 at an MOI of 1. Five days post-infection, the infected cells were examined under an inverted fluorescence microscope and by (E) flow cytometry and (F) Western blotting. The above experiments were performed three times, and a representative result is shown for each. (G, H and I) Different cell lines were infected with different MOIs (1, 0.1 and 0.01), and 72 h post-infection, their viral titers were determined by real-time PCR.