BLV-p24 expression in BLV infected cattle and detection of BLV-p24 receptors in cattle afflicted with tumorous leukosis in vivo.

Noncultivated and short-term cultivated blood leukocytes of BLV-infected cattle both with and without tumorous leukosis have been investigated for BLV-p24 antigen expression and for their capacity to bind BLV-p24 antigen. In animals with persistent lymphocytosis using cell extracts of 3-6 X 10(8) non-short-term cultivated blood leukocytes, BLV-p24 antigen could be identified by means of competitive RIA. In cattle with tumorous leukosis, the antigen detection in non-short-term cultivated leukocytes may be masked by the presence of antigen-binding receptors.

Bovine leucosis virus challenge infection of calves following application of BL-3 cells.

8 calves were vaccinated 3 times with 1.5.10(7) BL-3 cells.

Antibody production against BLV-p24 in calves following application of cell extracts from tumorous lymph nodes of cattle with enzootic bovine leukosis.

In the cell extract from tumorous lymph nodes of bovine leukosis virus (BLV)-infected cattle (tumour cell extract) and from lymph nodes of BLV-free cattle (control cell extract) neither the gp51 nor the p24 antigens were detectable. The tumour cell extract contained receptors for the BLV antigens gp51 and p24. The immunogenicity of the cell extracts was tested in calves.