The human papillomaviruses (HPV) are associated specifically with epithelial lesions, ranging from benign warts to invasive carcinoma. The virus encodes three late proteins, which are produced only in terminally differentiating keratinocytes, two of which are structural components of the virion. The third, E1-E4, is derived primarily from the E4 open reading frame, which represents a region of maximal divergence between different HPV types. E1-E4 does not seem to be a component of the virus particle or to be needed for transformation in vitro, but accumulates in the cytoplasm, where in certain benign lesions it can comprise 20-30% of total cell protein. We show here that expression of the HPV-16 E1-E4 protein in human keratinocytes (the natural host cell for HPV infection) results in the total collapse of the cytokeratin matrix. Tubulin and actin networks are unaffected by E1-E4, as are the nuclear lamins.

A glycoprotein H (gH)-deleted herpes simplex virus type 2 (HSV-2) was evaluated as a vaccine for the prevention of HSV-induced disease. This virus, which we term a DISC (disabled infectious single cycle) virus, can only complete one replication cycle in normal cells and should thus be safe yet still able to stimulate broad humoral and cell-mediated antiviral immune responses. A gH-deleted HSV-2 virus that has been tested as a vaccine in the guinea pig model of recurrent HSV-2 infection was constructed. Animals vaccinated with DISC HSV-2 showed complete protection against primary HSV-2-induced disease, even when challenged 6 months after vaccination. In addition, the animals were almost completely protected against recurrent disease. Even at low vaccination doses, there was a high degree of protection against primary disease. A reduction in recurrent disease symptoms was also observed following therapeutic vaccination of animals already infected with wild type HSV-2.

The vaccine potential of a mutant herpes simplex virus (HSV) type 1, with a deletion in the glycoprotein H (gH) gene, was evaluated. The virus requires a gH-expressing cell line for multi-cycle growth but can complete a single cycle of infection in noncomplementing cells. Such viruses, termed DISC (disabled infectious single cycle) viruses, should be safe, yet still able to stimulate humoral and cell-mediated responses against a broad range of virus antigens in vaccinated hosts. Prophylactic vaccination of guinea pigs with DISC HSV-1, by ear scarification or direct infection of the vaginal mucosa, afforded a high degree of protection against HSV-2-induced primary genital disease and reduced significantly the frequency of subsequent disease recurrence. There was also a trend toward reduced recurrence following therapeutic vaccination of animals already infected with HSV-2. DISC HSV vaccination, therefore, offers an effective route for control of HSV disease.

The presence and consistent expression of the genes encoding the human papillomavirus (HPV) E6 and E7 proteins in the great majority of cervical tumours presents the opportunity for an immunotherapeutic approach for control of the disease. This report describes the construction and characterisation of a recombinant vaccinia virus designed to express modified forms of the E6 and E7 proteins from HPV16 and HPV18, the viruses most commonly associated with cervical cancer. The recombinant virus (designated TA-HPV) was based on the Wyeth vaccine strain of vaccinia, and was shown to express the desired gene products. Studies in mice indicated that the recombinant virus was less neurovirulent than the parental virus and was capable of inducing an HPV-specific CTL response. This pre-clinical evaluation has provided a basis for the initiation of human trials in cervical cancer patients.

SUMMARYAthymic nude (nu/nu) mice were inoculated in the ear pinna with 104 p.f.u, herpes simplex virus type 1 (strain SC 16). Initially, the virus was observed to replicate in the pinna, spreading via a neurological route to the dorsal root ganglia, spinal cord, brain and adrenal glands. Following the transfer of lymphoid cells from day 7 herpesvirus-infected hairy immunocompetent donors into infected nude mice, virus was not isolated from the pinna and nervous system of the majority of the mice. The passive transfer of neutralizing polyclonal anti-herpesvirus Serum or neutralizing monoclonal anti-gp D serum did not reduce infectivity in the pinna, but markedly reduced the amount of virus in the ganglia and spinal cord. These data suggest that neutralizing antibodies play an important role in restricting the movement of virus to the nervous system, whereas cell-mediated immune (CMI) mechanisms are essential for eliminating virus from the pinna.