Vaccination trial with HPV16 L1E7 chimeric virus-like particles in women suffering from high grade cervical intraepithelial neoplasia (CIN 2/3).

Persistent infection with human papillomaviruses (HPV) is a prerequisite for the development of cervical cancer. Vaccination with virus-like particles (VLP) has demonstrated efficacy in prophylaxis but lacks therapeutic potential. HPV16 L1E7 chimeric virus-like particles (CVLP) consist of a carboxy-terminally truncated HPV16L1 protein fused to the amino-terminal part of the HPV16 E7 protein and self-assemble by recombinant expression of the fusion protein. The CVLP are able to induce L1- and E7-specific cytotoxic T lymphocytes. We have performed a first clinical trial to gain information about the safety and to generate preliminary data on the therapeutic potential of the CVLP in humans. A randomized, double blind, placebo-controlled clinical trial has been conducted in 39 HPV16 mono-infected high grade cervical intraepithelial neoplasia (CIN) patients (CIN 2/3). Two doses (75 mug or 250 mug) of CVLP were applied. The duration of the study was 24 weeks with 2 optional visits after another 12 and 24 weeks. The vaccine showed a very good safety profile with only minor adverse events attributable to the immunization. Antibodies with high titers against HPV16 L1 and low titers against HPV16 E7 as well as cellular immune responses against both proteins were induced. Responses were equivalent for both vaccine concentrations. A trend for histological improvement to CIN 1 or normal was seen in 39% of the patients receiving the vaccine and only 25% of the placebo recipients. Fifty-six percent of the responders were also HPV16 DNA-negative by the end of the study. Therefore, we demonstrated evidence for safety and a nonsignificant trend for the clinical efficacy of the HPV16 L1E7 CVLP vaccine.

Deletions within the epstein-barr virus latent membrane protein-1 oncogene in adult ordinary, HIV-associated and paediatric Hodgkin's disease.

The aims of this study were the following: a) to perform Epstein-Barr virus (EBV) strain type assignment in three groups of Hodgkin's disease(HD): adult ordinary (39 cases), paediatric (24 cases), and HIV-associated (30 cases) and to compare the prevalence of type 1 and type 2 in each of the groups with that existing in two reference populations made up of 50 adults and 39 children; b) to assess the frequency of latent membrane protein-1 (LMP-1) 30-base pair (bp) deletions in the HD groups and in the healthy controls; and c) to relate the presence of LMP-1 deletions with EBV type. Type 2 EBV was observed in 12.8% of ordinary HD, in 26.7% of HIV-associated HD, in 25% of paediatric HD, in 4% of adult controls, and in none of the healthy children. The existence of double infections by type 1 and 2 EBV was also observed in 5.1% of ordinary HD, in 6.7% of HIV-associated HD, and in 10% of adult controls. The 30-bp deletion was identified overall in 33.3% of ordinary HD, in 83.3% of HIV-positive HD, 79.2% of paediatric HD, 34.7% of adult controls, and 36.4% of healthy children. Statistical analysis showed a significant association of the deleted strains with HD occurring in HIV-positive patients (P= 0.00003) and childhood HD (P= 0.006). On the other hand, the prevalence of the 30-bp deletion in the adult ordinary HD group reflects the prevalence of the deletion in the general population. Co-infections by deleted and non-deleted EBV strains were detected in 12.8% of ordinary HD, in 33.3% of HIV-associated HD, in 50% of paediatric HD, in 26.5% of adult controls, and in 27.3% of healthy children. Concerning the relationship between the deletion and the EBV typing, 26% of type 1 specimens carried the 30-bp deletion in an isolated manner compared with 64.7% of type 2. The statistical analysis showed that the deletion was associated with type 2 strains when coinfections were excluded and only the cases in which the deletion appeared alone were considered (P=0.003).

A phase I trial of a human papillomavirus (HPV) peptide vaccine for women with high-grade cervical and vulvar intraepithelial neoplasia who are HPV 16 positive.

Eighteen women with high-grade cervical or vulvar intraepithelial neoplasia who were positive for human papillomavirus (HPV) 16 and were HLA-A2 positive were treated with escalating doses of a vaccine consisting of a 9-amino acid peptide from amino acids 12-20 encoded by the E7 gene emulsified with incomplete Freund's adjuvant. Starting with the eleventh patient, an 8-amino acid peptide 86-93 linked to a helper T-cell epitope peptide with a covalently linked lipid tail was added. Patients with colposcopically and biopsy-proven cervical intraepithelial neoplasia/vulvar intraepithelial neoplasia II/III received four immunizations of increasing doses of the vaccine each 3 weeks apart, followed by a repeat colposcopy and definitive removal of dysplastic tissue 3 weeks after the fourth immunization. Patients were skin tested with the E7 12-20 peptide as well as control candida, mumps, and saline prior to and after the series of immunizations. Peripheral blood mononuclear cells were obtained by leucopheresis prior to and after the series of immunizations for analyses of CTL reactivity to the E7 12-20 and 86-93 epitope sequences. The presence of HPV 16 was assessed by DNA PCR on cervical scrapings and the biopsy specimens after vaccination. Pathology specimens were analyzed before and after vaccination for the presence of dysplasia, and the intralesional infiltrate of CD4/CD8 T-cells and dendritic cells was measured by immunohistochemical staining. Only 3 of 18 patients cleared their dysplasia after vaccine, but an increased S100+ dendritic cell infiltrate was observed in 6 of 6 patients tested. Cytokine release and cytolysis assays to measure E7-specific reactivity revealed increases in 10 of 16 patients tested. No positive delayed type hypersensitivity skin test reactivity was shown in any patient to HPV E7 12-20 before or after vaccinations. Virological assays showed that 12 of 18 patients cleared the virus from cervical scrapings by the fourth vaccine injection, but all biopsy samples were still positive by in situ RNA hybridization after vaccination. Six patients had partial colposcopically measured regression of their cervical intraepithelial neoplastic lesions in addition to the three complete responders. The data establish that a HPV-16 peptide vaccine may have important biological and clinical effects and suggest that future refinements of an HPV vaccine strategy to boost antigen-specific immunity should be explored.

Mecanismos de oncogénesis viral / Mechanisms of viral oncogenesis

Actualmente se sabe que el 20 por ciento de los cánceres humanos están asociados con virus oncogénicos. El virus papiloma humano con cáncer anogenital, los virus de la hepatitis B y C con carcinoma hepatocelular, el virus Epstein Barr con carcinomas nasofaríngeos y linfomas, el virus de la leucemia-linfoma T con leucemias en el adulto. Un rasgo común en todos los tumores asociados con infección viral es el largo período de latencia entre la infección y la aparición de la neoplasia y la baja proporción de individuos infectados que desarrollan un tumor maligno. Estas observaciones indican que los virus oncogénicos son necesarios pero no suficientes para inducir cáncer, otros factores podrían estar involucrados. Esta actualización resume informaciones recientes acerca de los mecanismos de carcinogénesis viral, en particular, la interacción de oncoproteínas virales y proteínas supresoras tumorales. La inactivación de estas proteínas supresoras podría representar una estrategia común a través de la cual los virus tumorales pueden contribuir a la transformación maligna de la célula