Abstract
A comparative study on several virus-specific antigens of bovine and ovine leukemia viruses is presented. In addition to the major immunologically reactive, nonglycosylated antigen p21, which has a molecular weight of 21,000, both viruses share two glycoproteins of apparent molecular weights of 60,000 (gp60) and 32,000 (gp32), respectively. Immunological cross-reaction suggests that ovine and bovine leukemia viruses are genetically highly related.