Human Wart Virus: In vitro Cultivation

Immunoelectron microscopical localization of human papillomavirus type 16 L1 and E4 proteins in cervical keratinocytes cultured in vivo

The human papillomavirus (HPV) causes warts, but is also associated with the development of squamous cell dysplasia and carcinoma. The virus is host and tissue specific and the numerous HPV types show predilection for different body sites. Experimental production of HPV 16 particles is at present only possible using in vivo culture of keratinocytes containing episomal viral DNA. Using immunoelectron microscopy, we have investigated the localization of HPV 16 E4 and L1 proteins in a keratinized epithelium formed by grafting HPV 16-containing cervical keratinocytes onto the athymic mouse. New viral progeny are produced in this system, as confirmed by labeling of intranuclear particles with a mouse monoclonal antibody against the HPV 16 major capsid (L1) protein. The role of the E4 protein is not yet clear, although it is believed to be important for the later stages of the virus life cycle. Here we confirm its cytoplasmic localization in the cells of the spinous and granular layers and demonstrate co-localization with keratin tonofilaments.

The search for a culture system for papillomavirus

Papillomaviruses induce tumors of keratinocytes. Vegetative viral DNA replication and virion assembly are seen in those cells which are in the process of keratinizing or are keratinized. To date, no cell culture system has been developed that permits expression of the complete viral life cycle. Keratinocytes infected in culture may harbor the virus as a stable, replicating episome, but they do not support vegetative viral growth, nor do they become immortalized or transformed. The major obstacle in using keratinocyte cultures may be related to a dual need for transformation and full differentiation. Some animal papillomaviruses have been shown to be capable of transforming cultured murine fibroblasts. The fibroblast model is useful for identifying the viral-transforming gene(s) and their products.

Dinitrochlorobenzene and debulking therapy of conjunctival papilloma

A conjunctival papilloma in a four-year-old boy had recurred despite one surgical removal, and three cryosurgical treatments. After sensitization of the child's lymphocytes to dinitrochlorobenzene (DNCB), the lesion responded rapidly and completely to debulking followed by painting the base of the tumor with DNCB. We feel that the effectiveness and simplicity of debulking and DNCB treatment of conjunctival papillomas, which have resisted previous standard forms of therapy, gives an easy, relatively inexpensive, and rapid method of treating these lesions.

Human papova (wart) virus

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