Page 1170 - Veterinary Immunology, 10th Edition
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expression plasmid engineered to encode the human tyrosinase
VetBooks.ir gene. Four doses are administered transdermally by a needle-free
device and boosted at six-monthly intervals. The plasmid contains a
cytomegalovirus promoter and a kanamycin resistance selection
marker. The plasmid encodes the human tyrosinase gene, and as a
result promotes the synthesis of this enzyme in the recipient
animal. Vaccinated dogs then mount an immune response against
this foreign tyrosinase. Tyrosinase catalyzes the hydroxylation of
tyrosine to dihydroxy-phenylalanine, which is a key step in
melanin production. The immune response to the tyrosinase
induces both antibodies and cytotoxic T cells against the dog's
melanoma cells, and this may prevent tumor recurrence.
The USDA has also approved a DNA vaccine directed against
canine B cell lymphomas. The antigenic target is CD20. This is
expressed in immature B cells and is present in about 70% of B cell
lymphomas.
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