Page 1169 - Veterinary Immunology, 10th Edition

effectiveness.
VetBooks.ir Antibody Therapy

Monoclonal antibodies can be used to destroy tumors, either when
given alone or when complexed to highly cytotoxic drugs or potent

radioisotopes, which they carry directly to the tumor cells. One of
the first such monoclonal antibodies to be produced was directed
against canine T cells (CL/MAb231) and produced encouraging
results when used to manage lymphomas in dogs. It apparently
worked by inducing ADCC and complement-mediated lysis. New

monoclonal antibodies against lymphomas in dogs are currently
undergoing clinical trials. One is directed against CD20 in B cells
and another is directed against CD52 on T cells. Other potential

animal tumor targets include CD47 in B cell lymphomas, epithelial
cell growth factor receptor in mammary carcinomas, and
carcinoembryonic antigen for colon carcinomas.

Immunoprevention

In contrast to the techniques described previously, most of which
have met with only limited success, there are established successful
techniques for vaccination against tumor viruses. These include

such effective vaccines against viral antigens such as hepatitis B and
human papillomavirus, the causes of hepatocellular carcinoma and
cervical cancer, respectively. The most important of these in
veterinary medicine are the vaccines against feline leukemia. These
vaccines usually contain high concentrations of the major viral

antigens, and immunity is almost entirely directed against viral
glycoproteins. Other important vaccines are those directed against
Marek's disease, a T cell tumor of chickens caused by a herpesvirus.

The immune response evoked by these vaccines has two
components. First, humoral and cell-mediated responses act
directly on the virus to reduce the quantity available to infect cells.
Second, an immune response is provoked against virus-coded
antigens on the surface of tumor cells. Both the antiviral and

antitumor immune responses act synergistically to protect the birds.
A vaccine designed to enhance survival in recurrent melanoma is
available for use in dogs. This vaccine consists of an Escherichia coli

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