Abstract: The present invention involves a recombinant virus which comprises at least one foreign nucleic acid inserted within a non-essential region of the viral genome of a virus, wherein each such foreign nucleic acid encodes a protein. The protein which is encoded is selected from the groups consisting of a feline CD28 protein or an immunogenic portion thereof, a feline cD80 protein or an immunogenic portion thereof, a feline CD86 protein or an immunogenic portion thereof, or a feline CTLA-4 protein or an immunogenic portion thereof. The protein is capable of being expressed when the recombinant virus is introduced into an appropiate host. The present invention also involves a recombinant virus further comprising a foreign nucleic acid encoding an immunogen derived from a pathogen. The present invention also comprises recombinant viruses which are capable of enhancing an immune response in a feline.

Abstract: The present invention provides isolated and purified DNA encoding feline CD80 (B7-1) ligand, feline CD86 (B7-2) ligand, feline CD28 receptor, or feline CTLA-4 (CD 152) receptor, as well as vectors comprising nucleic acid encoding feline CD80, feline CD86, feline CD28, or feline CTLA-4. The present invention provides a host cells transformed with CD80-encoding vectors, CD86-encoding vectors, CD28-encoding vectors, or CTLA-4-encoding vectors. The invention provides polypeptides encoded by the nucleic acid of feline CD80, feline CD86, feline CD28, or feline CTLA-4. The present invention provides a vaccine comprising an effective amount of polypeptides encoded by the nucleic acid of feline CD80, feline CD86, feline CD28, or feline CTLA-4. The present invention also provides vaccines which further comprise immunogens derived from pathogens. The invention provides for vaccines capable of enhancing an immune response. The invention also provides for vaccines capable of suppressing and immune response.