VZV replication in SOC. Tissues were inoculated by intradermal injection (circles) or scarification (triangles). The PFU/tissue was determined by standard plaque assay; each symbol represents one tissue. The doubling times were measured between 2 and 6 days (brackets).

Immunohistochemistry of VZV-infected skin organ cultures. Tissues were mock-infected (A) or VZV-infected (B to F) and processed for immunohistochemistry on day 6 after inoculation. Virus antigens were detected with a high-titer human serum and visualized with the chromogen Vector Red, then counterstained with hematoxylin. Using a 20× objective, VZV-positive cells and debris (black arrows) were found in lesions (B), the epidermis, and hair follicles (D). Details within the white boxes are shown under higher magnification (C, E, and F, 40×).

Histological analysis of VZV-infected skin organ cultures. Skin tissues were mock-infected (A to D) or infected with VZV (E to H), and then processed for histological analysis on days 0, 2, 4, and 6 after inoculation. Sections were stained with hematoxylin and eosin and examined by light microscopy and digital photomicrography. From the top down, the tissue compartments are sheets and whorls of keratin (pink), epidermis (blue), and dermis (pink), and hair follicles are oval structures in the dermis. Mock-infected tissues were unchanged over 6 days, while lesions formed in the VZV-infected tissue (white arrow). The black arrow indicates destruction of hair follicles. These sections are representative of more than 20 tissues examined. Magnification, 20×.

Electron microscopy of VZV in SOC. Tissues were infected for 6 days and then examined by electron microscopy. (A) Stages of VZV assembly were observed in an infected keratinocyte in the nucleus (N) and the cytoplasm (C), and the areas within boxes 1 to 3 are shown at higher magnification in the corresponding panels. Capsids formed in the nucleus and a DNA-containing capsid were adjacent to the inner nuclear membrane (1, white arrowhead). Enveloped virions were found in cytoplasmic vesicles (2 and 3, black arrowheads). Extracellular, intact virions are found in the spaces between cells (2 and 3, white arrowheads). Viral envelopes were also found in the intercellular spaces. (B) An uninfected dermal fibroblast (left) was coated with VZV particles and an extracellular (Ex) mass of VZV virions and viral debris was adjacent. The area within the box is shown at high magnification (right) and white arrowheads indicate three complete virions. The magnifications are labeled and the lengths of the black bars indicate relative size.