Electron-microscopic study of Herpesvirus macaca in human fibroblasts

An electron microscopic study of the morphology of Herpesvirus macaca, a serologically distinct infectious agent isolated from the leukocytes of rhesus monkeys, was performed. WI-38 fibroblast monolayers were infected with the virus and examined 18 days later. The morphology of Herpesvirus macaca was, in general, typical of the herpesvirus group. Enveloped virus particles observed via negative-stain technique had a diameter of 145-155 nm. An inner capsid composed of hexagonal capsomeres had a diameter of 100-110 nm and surrounded a central core. While enveloped forms appeared to be present within the nuclei of infected cells, they were not found in the cytoplasm except within vacuolar structures. Associated changes were found in the morphology of infected cells, including intracytoplasmic myelin figures.