Immunogenic proteins of feline rhinotracheitis virus

Feline rhinotracheitis virus is an upper-respiratory-tract pathogen of cats. It may also cause generalized infections or abortions. Antigens present in [35S]methionine- or [14C]glucosamine-labeled purified virions, in Nonident P-40 (NP-40) extracts of a mixture of virions and infected cells, and in virion-free cell culture medium, along with mock-infected Crandell -Rees feline kidney cell controls, were analyzed by direct sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) or by SDS-PAGE preceded by Staphylococcus aureus protein A immunoprecipitation. The direct SDS-PAGE analysis revealed at least 17 virus-specific peptides with molecular weights ranging from less than 200,000 ( 200K ) to more than 30K . Three of these peptides were glycosylated and had molecular weights of 105K , 68K , and 60K. Immunoprecipitates of purified virions and NP-40 extracts contained three major glycoproteins with the same estimated molecular weights as those found by the direct analysis. A prominent 105K glycoprotein was present in virion-free cell culture medium immunoprecipitates. In addition, a number of nonglycosylated feline rhinotracheitis virus-specific polypeptides (eight in virions, three in NP-40 extracts, and nine in virion-free cell culture medium), ranging in molecular weight from 145K to 32K, were present in the various immunoprecipitates.