DIAGNOSTIC ROLE OF CIRCULATING IMMUNE COMPLEXES DURING COW LEUKEMIA

In chronic infections caused by retroviruses, "antigen antibody" immune complexes (AAC) appear in body fluids. In the course of the studies to clarify the structure of the AAC we proved that immune complexes in cattle leukemia could contain the virus's viral DNA. The role of circulating immune complexes in the pathogenesis of the bovine leukemia virus (BLV) infection is not sufficiently studied. AAC containing the viral DNA may be formed during the death of infected B-lymphocytes by linking non-invasive viral DNA to surface IgMs with high DNA affinity. Determining the appearance of AAC with the viral DNA in biological fluids depending on the stages of the infectious process is an important criterion in antileukemia measures. The article describes the results of research to determine circulating immune complexes containing the provirus DNA in the milk of cows infected with BLV as compared with hematological changes at different stages of the infection process. It is reported that the viral DNA in the AAC of the milk of cows infected with BLV is detected much earlier than hematological changes that allow to consider them leukemia patients. Of the 12 cows studied, by the end of the experiment, six cows had AAC containing the viral DNA in their milk samples. And only one cow with the detection of the viral DNA in the AAC of milk showed parallel hematological changes typical for leukemia. The use of milk samples for molecular genetic analysis to identify BLV in AAC is quite a promising area for assessing the epizootic situation on farms and is very informative in determining the animal status.