Protective effect of Mx1 transgene against CSFV infection. (A) IFA and FITC conjugated antibodies were used to examine the viral infection in fibroblasts from 5 transgenic and an age-matched non-transgenic pigs; 4 × magnification. (B) Quantification of CSFV-positive cells. Values represent the mean ± s.d., n = 3. *P < 0.01 vs non-transgenic.