FIG 3.
Influenza A viruses encoding Belzig-NP escape restriction in MxA-transgenic mice. (A and B) C57BL/6N (B6) mice lacking functional Mx proteins and B6 mice homozygous for the human MxA transgene (hMxtg+/+) were challenged intranasally with 104 PFU of the indicated viruses with the H7N7 (A) or rBelzig (B) backbone. Viral titers in the lungs at 3 days postinfection were determined via plaque assay. Error bars indicate the standard errors of the means for at least four mice. The fold decrease in the titer in hMxtg+/+ mice from that in B6 mice is shown at the top. Student’s t test was performed to determine the P value for the difference between B6 and hMxtg+/+ mice. *, P < 0.05; ***, P < 0.001.