Fig. 4
The recombinant and attenuated strains did not cause systemic inflammation in mice. a Five-week-old SPF-ICR mice were inoculated with 1 × 105 TCID50 viruses by intramuscular injection in the right hind leg. The control group (Mock) was injected with 100 μL DMEM. When the PRV-Fa-infected mouse group was found to start scratching (about 72 hpi), the surviving mice's organs were collected, 10 mg tissues were used to extract RNA, 100 ng cDNA generated from reverse transcription were used for qPCR to examine IL6 transcription. b The serum IL-6 was detected by ELISA after about 200 μl blood was collected from the orbit of control or virus-infected mice. c H & E staining showed that the infection of PRV-Fa could lead to the infiltration of immune cells in the brain of mice. The black arrow in the figure indicated the immune cell infiltration. Unpaired t-test was performed by GraphPad Prism 5.0, GraphPad Software (San Diego, CA, USA), *p < 0.05 (n = 5/each group)