STRUCTURAL PROTEINS OF ADENOVIRUSES .3. PURIFICATION AND CHARACTERIZATION OF ADENOVIRUS TYPE-2 PENTON ANTIGEN

The penton antigen from adenovirus type 2 has been purified by DEAE chromatography, agarose chromatography and preparative polyacrylamide electrophoresis. The final product is homogeneous by electron microscopy, immunoelectrophoresis, polyacrylamide electrophoresis, and analytical ultracentrifugation. Penton antigen so prepared has a sedimentation coefficient of 10.5 and a molecular weight around 400,000. A minimum of three antigenic specificities can be demonstrated with immunodiffusion. Trypsin selectively inactivates the cytopathic effect of the type 2 penton. At high trypsin concentrations the main part of the vertex capsomer antigenicity and morphology is also lost. Rabbit antisera to pure pentons contain low titers of neutralizing antibodies when assayed by inhibition of plaque formation. The use of the fluorescent focus assay reveals, in contrast, high neutralizing activity in these sera. Treatment of penton antigen with pyridine releases free vertex capsomers which are immunologically and morphologically intact and have the ability to induce cytopathic changes in KB-cell cultures. © 1969.