MOLLUSCUM CONTAGIOSUM - NORMAL AND VIRUS INFECTED EPIDERMAL CELL KINETICS

[摘要] Virus-infected and normal epidermal cell kinetics were determined in molluscum contagiosum by intradermal injections of thymidine-H3 and cytidine-H3 to label nuclear and viral DNA and RNA. In the basal layer the germinative cell renewal time proved more rapid than normal (average 3.4 days). Viral inclusions became labeled only in the Malpighian layer. These labeled infected cells moved upward in a band leaving the granular layer within 5 days and the horny layerin 9 to 15 days. In contrast, labeled nuclei of uninfected cells required 9 to 30 days to reach the granular layer. Virus replication occurs in the Malpighian layer. Nuclear DNA is not utilized for virus production. All inclusions in the Malpighian layer contain labels for 24 but not 48 hr., suggesting that infectious particles are transferred from cell to cell. Infection shuts off transcription of RNA from the host cell genome. Some RNA is formed in the cytoplasm, presumably under viral direction. Two populations of cells exist: infected cells which move rapidly and as a unit; and uninfected cells which move more slowly and apparently randomly. The findings are discussed in terms of how normal epidermal cells related to each other during differentiation.