WHETHER IS IT POSSIBLE TO PREVENT LEUKOSIS?

O.Shapovalova, N.Myagkikh, P.Zdanevich, V.Busol
Institute of Experimental & Clinical Veterinary Medicine, 83, Pushkinskaya str., 61024, Kharkov, Ukraine.
Fax: (0572)475508, e-mail: apb@venera.kharkov.ua

Blood cancer or leukosis is a diagnosis with a terrible verdict. This disease may be caused by different factors including radioactive irradiation, hereditary predisposition, chemical mutagenesis, etc. Among these, the viral nature of leukemia of both man and animal is of particular interest.

Is the causative agent of bovine lymphoid leukosis, the retrovirus, which is of a similar nature as the immunodeficiency virus responsible for AIDS, a serious hazard to human health?

Is it possible to drink milk and to eat meat from the cows suffering from this disease?

May it jeopardize our children health?

Are any other animal products safe and healthy for use?

How to protect the cows against leukosis, to stop infection transmission in herds, areas, regions?

If the antibiotics are powerless to the virus, what else the scientists can do?

How does the leukosis develop?

The complex immunological mechanisms initiating since the moment of virus invasion an organism make a contribution to leukemia pathogenesis.

Even seven leukemia virus-infected lymphocytes will suffice for the onset of disease in the blood of unprotected organism.

The humoral immune response induced after long incubation period of disease does not destruct the virus but allows its penetration into hemopoietic tissue, thus attacking the main precursors of lymphocytes, basic barrier cells against any disease.

The bovine leukosis cannot be cured but it can be prevented.

How to protect the cows against infection?

Young animals are protected against virus infection by colostric immunity up to the 6-month age. But the mere presence of leukosis-infected animal in a herd or in a farm is sufficient to infect the others that is followed by chain infection transmission, infected generation in succeeding years and, thus, production of milk and meat containing carcinogenic metabolites which may constitute a threat to human life.

Only effective timely-made vaccination causing formation of protective cells and antibodies shows promise of preventing the bovine leukemia .

New vaccine against the bovine leukosis has been developed by a research group from the Institute of Experimental and Clinical Veterinary Medicine {Kharkov, Ukraine}.

The new vaccine :

_ does not contain any live virus;

_ is safe for animal;

_ induces antiviral immune response actively depressing the virus invading an organism;

_ two subcutaneous vaccine injections are sufficient;

_ intensity of the humoral immune response can be tested by immunodiffusion reaction in agar gel;

_ duration of vaccine protective action is about 2 years;

_ the vaccine contains chemically modified envelope glycoprotein of bovine leukosis virus as an antigen on the specific sorbent with immunomodulated properties.