Biophysical and serologic comparison of four equine adenovirus isolates

Four equine adenovirus isolates have been characterized with regard to their biophysical and serologic properties. Electron microscopic studies demonstrated that purified virions have a typical adenovirus morphologic characteristic, with 50-nm-long fiber projections at each vertex of an 80-nm-diameter icosahedron. Extracted viral DNA was found to be a linear duplex of molecular weight 21 to 22 x 10(6). All four isolates were found to have a buoyant density in CsCl of 1.346 +/- 0.002 g/ml. Hexon structural components prepared from each isolate were shown to carry the same relative net charge, as judged from anion exchange elution profiles. Sodium dodecyl sulfate (sodium lauryl sulfate)-polyacrylamide gel electrophoresis revealed that the four isolates were composed of which the electrophoretic migration pattern was distinct from that of a human adenovirus reference. Serologic data (serum-neutralization and hemagglutination-inhibition tests) did not reveal any distinct antigenic diversity among the four isolates. On the basis of data obtained in this study, it is proposed that equine adenovirus isolates thus far available do, in fact, constitute a single serotype.