Detection of bovine leukemia virus antigen in urine from naturally infected cattle.

A competitive radioimmunoassay was used to detect the major internal protein (p25) of bovine leukemia virus (BLV) in urine from infected cattle. Whole urine samples from six out of seven infected cattle were found to contain the BLV p25 antigen. Analysis of different fractions of urine indicated that p25 was present in a soluble form as well as in the high-speed pellet, but not in the low-speed pellet. Similar results were obtained with urine samples collected from a BLV-infected cow by catheterization of the bladder.