Properties of two isolated antigens associated with bovine leukemia virus infection

We isolated an ether-resistant internal antigen and an ether-sensitive antigen previously described in relation to bovine leukemia virus infection. These two antigens have now been isolated by isoelectric focusing and concanavalin A affinity chromatography, respectively. The ether-resistant antigen exhibited isoelectric heterogeneity with a major peak at pH 7.2 and a minor peak at pH 6.2. Its molecular weight, estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), was 23,000 (p23), and it gave a sedimentation value of 2.3s. For material containing ether-sensitive antigen, analyzed by SDS-PAGE, protein staining revealed four components with molecular weights of 18,000, 25,000, 45,000, and 55,000. Two of these [45,000 (gp45) and 55,000 (gp55)] were stained by periodic acid-Schiff reagent. Isoelectric point and sedimentation value of the major glycoprotein (gp45) were pH 5.0 and 3.4s, respectively; no immunologic cross-reactivity was found between p23 and glycoprotein antigen.