The Art and Science of Obtaining Virion Stocks for Experimental Human Papillomavirus Infections
Michelle A. Ozbun and Michael P. Kivitz
from: Small DNA Tumour Viruses (Edited by: Kevin Gaston). Caister Academic Press, U.K. (2012)
Some human papillomaviruses (HPVs) have been propagated in the laboratory for ≈20 years; currently, there are multiple means for obtaining infectious virion stocks for experimental infections. Processes dependent upon epithelial differentiation for achieving virion production include natural warts, rodent xenografts, and cultured organotypic epithelial tissues. However, these options are not amenable for every HPV genotype, and virion yields are variable and viral genotype-dependent. Differentiation-dependent laboratory approaches are limited to virus production from replication-competent viral genomes and typically only viral genomes capable of conferring a significant cellular growth advantage can be maintained long-term. Cutaneous HPV and animal PV lesions yield the highest virion levels and pure stocks can be obtained for many cutaneous PVs. Only crude, low-purity virion stocks have been reported for carcinogenic HPVs (e.g., types 16, 18, 31) typically via organotypic tissue propagation. Advances in virion production methods independent of epithelial differentiation permit the isolation of high-titer, high purity viral stocks from virtually any cloned PV genotype. Based on the self assembly of transiently expressed capsid proteins to package DNA molecules of ≈5- to 8-kb in size, this approach provides the ability to produce infectious particles encapsidating any viral or reporter genome regardless of its replicative ability. These particles share many structural and functional similarities with differentiation-induced virions; however, questions remain about the absolute physiological likeness among PV stocks derived by different means. Herein we discuss advantages and disadvantages among the varied means of virion production, detail known similarities, and make note of potential disparities that have yet to be tested read more ...