Cloning and sequence analysis of the spike gene from several feline coronaviruses.
The DNA sequence encoding the spike gene from the DF2 strain of Type II feline infectious peritonitis virus (FIPV), a temperature sensitive FIPV virus (TS-DF2) and an isolate of feline enteric coronavirus (FECV 1683) were determined. Comparison of the published WSU 1146 and DF2 FIPV S genes showed that the viruses shared a high degree of homology (99.6%). Likewise, the S gene of the virulent DF2 FIPV virus was closely conserved to that isolated from the vaccine virus strain, TS-DF2 FIPV. In contrast, the FECV S gene had numerous DNA and amino acid differences when compared to the virulent FIPV sequences. Sequence differences among the feline coronavirus isolates were localized to the amino-terminus region of the S gene.