Immunobiology of Papillomaviruses
Margaret A Stanley
from: Papillomavirus Research: From Natural History To Vaccines and Beyond (Edited by: M. Saveria Campo). Caister Academic Press, U.K. (2006)
HPV infection is ubiquitous. In the genital tract almost all sexually active indivuals are infected at some point but most clear their infections without overt clinical disease. Lesions in which productive viral infection is occurring (ano-genital warts and CIN1) are not associated with inflammation or histological evidence of immune activity and HPV evades immune recognition by evading innate immune defences and delaying the activation of adaptive immunity. Regression of ano-genital warts is accompanied histologically by a response characteristic of cell mediated immunity, animal models support this and provide evidence that the response is regulated by CD4 T cell-dependent mechanisms. The increased prevalence of HPV infections in individuals immunosuppressed either as a consequence of organ transplantation or HIV infection demonstrates the central importance of the CD4 T cell population in the control of established HPV infections. Although it seems clear that the CD4 T cell subset is critical for the induction and regulation of the host response to HPV the nature of the effector response remains unclear. There is increasing evidence that NK cells and antigen specific CTLs recognising E2 and E6 are important effectors but CTL responses and the target antigens are still poorly understood read more ...