Fig. 4. Recombinant L. plantarum NC8-409IC and NC8-409p’I inhibit TGEV infection (at the gene level).

IPEC-J2 cells were treated with recombinant L. plantarum NC8-409IC and NC8-409p’I (at a ratio of recombinant protein to IPEC-J2 cells of 1:10) for 2 h in 24-well plates and were then inoculated with TGEV strain SY at 100× TCID50. Cells were cultured for 36 h prior to CFS collection. Viral RNA was quantified by real-time quantitative PCR. The virus infection rate was calculated (A). Cells were incubated with the indicated doses (at ratios of recombinant protein to IPEC-J2 cells from 1:160 to 1:10) of recombinant L. plantarum NC8-409IC for 2 h prior to infection with TGEV at 1000× TCID50. The level of TGEV RNA in the CFS was quantified by Q-PCR (B). Intracellular viral RNA was quantified by Q-PCR, and the virus infection rate was calculated (C). The statistical method for evaluating the results is the same as that used for the data in Fig. 4 above.