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3.4 HEALTH BIOTECHNOLOGY
Human papillomaviruses (HPVs) are ubiquitous, sexually transmitted viruses present in 99.7% of all cervical cancers, the second most common cancer in females worldwide. Expression of HPV L1 and L2 late genes is found only in terminally differentiated epithelial cells. As L1 and L2 proteins are highly immunogenic, it is suggested that their suppression may prevent detection of the virus by the immune system, thus acting as a prerequisite for persistence of infection. Therefore, if expression of these proteins in the lower cervical layers was induced, it could lead to clearance of the virus. One aim of this thesis was to investigate potential inducers of late gene expression in HPV-16. Functional stable cell lines containing plasmids, in which L1 is replaced by a CAT reporter gene, were treated with an array of small molecule drugs. TPA and retinoic acid were found to be inducers of late gene expression, with potential as treatments for persistent HPV infection. An additional aim of the study was to investigate the role and distribution of invariant Natural Killer T (iNKT) cells in cervical epithelium. iNKT cells are potent activators of the immune system with a predominately protective function. However, their presence may be downregulated in HPV positive epithelium, possibly helping infected cells evade protective immunological surveillance. As there is currently no available means to determine iNKT cell existence in human tissue, the objective was to develop a novel method for their detection, useful for subsequent enumeration of iNKT cells in HPV-infected cervical cancer samples. Cell blocks containing a pure population of iNKTs were initially created for use as positive controls. The staining potential of the 6B11 antibody, which targets the iNKT T cell receptor (Vα24-Jα18), was then examined for use in both iNKT cell block sections and a range of human tissue. Investigations through automated staining returned positive results in gastric and tonsil tissue, showing potential use for 6B11 as an innovative technique of iNKT cell detection in human tissue.
Nolan, P. (2015). The Regulation of HPV Late Gene Expression and the Potential Role of iNKT Cells in Cervical Cancer Masters dissertation. Technological University Dublin. doi:10.21427/D7089C