Demonstration of a thymus cell tumour in BLV-infected cattle.

Occurrence of thymus cell tumours was followed in cattle with enzootic leukosis using a thymus-specific antiserum. Among 32 tumorous lymph nodes investigated, one could be identified as a thymus cell tumour. In the DNA extract from this tumorous lymph node BLV-specific sequences have been demonstrated. This finding disproved the hitherto assumption that BLV-induced lymph node tumours of cattle were derived exclusively from B-lymphocytes.