has role protective antigen role protective antigen Feline leukemia virus protein Env Oliver He Protegen ID: 465; NCBI Gene GI: 1491868; NCBI Protein GI: 9630709; NCBI Protein Accession: NP_047256; NCBITaxon: 11768 protein Allen Xiang Study describes experiments which demonstrate that the vaccine, (EURIFEL FeLV; Merial) that expresses the FeLV env and gag protective genes, is effective against any oronasal FeLV challenge. The protection was shown to be solid against an oronasal challenge one year after the initial vaccination, and was effective against a very severe 'in-contact' challenge [PubMed: 12934796].