Electron microscopy of mouse thymic virus

Thymuses of mice infected with mouse thymic virus (MTV), a herpesvirus, were examined with the electron microscope. Damage was manifested by distortions of cells, nuclei, and other organelles, with cellular aggregation apparent at advanced stages of necrosis. Infected cells also contained MTV particles and filaments. Negative staining showed that naked MTV capsids were icosahedral in shape with diameters ranging from 95 to 110 nm. Enveloped capsids appeared spherical and ranged in diameter from 125 to 165 nm. Immunogold labeling revealed the presence of antigenic sites around both naked and enveloped capsids, and also on the 10 nm filaments. The use of electron microscopy and immunohistochemical techniques as diagnostic tools to demonstrate MTV infection could prove valuable for the detection of the infection and the study of its pathogenesis.