摘要

The spike gene(S)of Infectious bronchitis virus(IBV)CK/CH/LDL97Ⅰ/97 isolate was amplified,cloned,sequenced and analyzed.Results showed that the S gene was 3501 bp encoding a polypeptide of 1167 amino acids.The precursor of the S protein was cleaved into S1 and S2 fragments,which comprised 541 and 62...