TPM1 and infection: In our study, the abundance of alpha-tropomyosin was increased much more strongly with highly virulent IBV ck/CH/LDL/97I P5 infection than with the attenuated P115 strain, it is likely that it help to orchestrate virus assembly, release and efficient cell-to-cell spread, also may due to the different virulence between IBV ck/CH/LDL/97I P5 and P115 strain.