Cervical response to vaccination against HPV16 E7 in case of severe dysplasia.

OBJECTIVE: To evaluate the tolerance to vaccination against human papillomavirus (HPV)16 E7 (in SB adjuvant ASO2B) and its histological and immunohistological effects on HPV16 associated high-grade cervical dysplasias associated with HPV16. STUDY DESIGN: Five patients with histologically demonstrated severe cervical dysplasia (CIN3) HPV16 positive were injected three times before conization was performed 2 months after the first injection. We studied cytological, histological, proliferative pattern and immune profile before and after vaccination. The slides were compared with those obtained from non-injected patients. RESULTS: The injections were well tolerated and the specimens displayed a limited regression of the lesions. Nevertheless, massive CD4 and CD8 T cell lymphocytic infiltration was noticed after vaccination. DISCUSSION: We conclude that the vaccination we used provides an obvious immune histological reaction in the HPV infected cervix and that the 2 months delay before the final step (conization) is done is probably too short.

[Vaccination against human papillomavirus and against the cellular proliferation that it induces: facts and expectations]. / La vaccination contre les papillomavirus humains et contre les proliférations cellulaires qu'ils induisent : faits et espoirs.

Vaccination against human papillomavirus (HPV) give promising results in animal models. Prophylactic vaccination uses essentially virus-like particles autoassembled from the L1 capsid protein in its native form. Protection is achieved: it is efficient, type-specific and humoral. Therapeutic vaccination is of cellular origin and raised against the E7 oncoprotein. Several vaccine preparations have been found to be efficient: they include virus-like particles formed with L1-E7 fusion protein, E7 encoding plasmidic DNA, dendritic cells pulsed with E7-derived peptides,.

Indoor radon in the region of Brussels.

The indoor radon (222Rn) concentration has been measured by charcoal detectors in 278 buildings in the region of Brussels, Belgium. The correlation with the nature of the subsoil can be studied in detail thanks to the available geotechnical map. With a geometrical mean indoor radon concentration of 19 Bq m(-3), Brussels can be considered as generally unaffected by the radon problem. No value higher than 400 Bq m(-3) (the EU reference level for existing houses) was measured in an occupied room. However, two factors that may enhance the risk are identified: the absence of a basement or a ventilated crawl space, and the presence of loess, under the house. About one third of the houses without basements or ventilated crawl spaces built on loess show an indoor radon concentration above 200 Bq m(-3) (the EU reference level for new houses).

HPV-16 E7 but not E6 oncogenic protein triggers both cellular immunosuppression and angiogenic processes.

HPV-16 E6 and E7 oncoproteins impair the cell cycle in human uterine cervix carcinoma cells (HUCC) by acting on p53 and retinoblastoma proteins, respectively. We recently reported that E7 related into the extracellular compartment by HUCC SiHa cells could inhibit immune T-cell response to recall and alloantigens by a mechanism involving an overproduction of the immunosuppressive IFN alpha by antigen presenting cells (APCs). In this study, we found that besides E7, E6 protein and the vascular endothelium growth factor (VEGF) were released into the SiHa cell supernatants, and we further showed that extracellular E7 but not E6 oncoprotein 1) inhibits the immune cell response to recall and alloantigens, and 2) enhances the release of angiogenic cytokines, including TNF alpha, IL-1 beta and IL-6 by macrophages and/or dendritic cells. VEGF unexpectedly released by cancer cells could also contribute to angiogenesis. Thus in HUCC the same E7 oncoprotein which contributes to controlling the cancer cell cycle has the means in its extracellular configuration to contribute to microenvironmental immunosuppressive and angiogenic processes. Neutralizing anti-E7 antibodies either passively administered or induced by active immunization could represent a new immunotherapeutic endeavour to combat the immunosuppression and/or neoangiogenesis effects of extracellular E7 protein.

Induction of cellular immunosuppression by the human papillomavirus type 16 E7 oncogenic protein.

The human papillomavirus type 16 (HPV-16) E7 oncogenic protein is found in the culture supernatant of SiHa cells, a cervical carcinoma cell line. Extracellular E7 protein, acting as a viral toxin in human immune cells, induces the overproduction of the immune suppressive IFN alpha cytokine by APCs, and inhibits the T-cell response to recall and allogenic antigens. These effects should be taken into account for the design of anti-human cervical carcinoma vaccines.

Transfer of the murine interleukin-12 gene in vivo by a Semliki Forest virus vector induces B16 tumor regression through inhibition of tumor blood vessel formation monitored by Doppler ultrasonography.

To elucidate further the potential of a Semliki Forest virus (SFV) vector in vivo for gene therapy, we constructed a vector, SFV-IL12, to transfer murine IL-12 genes into tumors. A single intratumoral injection of established B16 murine melanoma with SFV-IL12 resulted in a significant inhibition of tumor growth, while injection with SFV-LacZ had no effect. This antitumoral activity correlated with an increase of IFN gamma production, MIG and IP-10 mRNA expression, both at the tumor site and at the periphery. In contrast, no increase in CTL- or NK cell-mediated cytotoxic response could be detected, ruling out the involvement of T and NK cell cytotoxicity. To determine how the transfer to IL-12 genes induced tumor regression, the antiangiogenic-activity of SFV-IL12 was investigated using Doppler ultrasonography (DUS). SFV-IL12 inhibited in situ neovascularization within the tumor, without affecting the resistance index of pre-existing intratumoral blood flows. In addition, histological analysis of SFV-IL12-treated tumors showed massive tumor necrosis induced by SFV-IL12 treatment. These data indicate that SFV-IL12 inhibits tumor growth through its antiangiogenic activity, demonstrated for the first time in vivo by DUS, and suggest that the SFV vector may be a novel valuable tool in tumor gene transfer.

Interleukin-12-secreting human papillomavirus type 16-transformed cells provide a potent cancer vaccine that generates E7-directed immunity.

The development of a vaccine that would be capable of preventing or curing the (pre)cancerous lesions induced by genital oncogenic human papillomaviruses (HPVs) is the focus of much research. Many studies are presently evaluating vaccines based on the viral E6 and E7 oncoproteins, both of which are continually expressed by tumor cells. The success of a cancer vaccine relies, in large part, on the induction of a tumor-specific Th1-type immunity. In this study, we have evaluated the ability of B7-related and/or interleukin-12 (IL-12)-expressing, non-immunogenic murine HPV16-transformed BMK-16/myc cells, to achieve this goal. BMK-16/myc cells engineered to express surface B7-1 or B7-2 molecules remain tumorigenic in syngeneic BALB/c mice, suggesting that expression of these molecules alone is not sufficient to induce tumor regression. In contrast, mice injected with tumor cells engineered to secrete IL-12 remained tumor-free, demonstrating that IL-12 expression is sufficient to induce tumor rejection. IL-12-secreting BMK-16/myc cells were further shown to induce potent and specific long-term tumor resistance, even after irradiation. B7-1 was found to slightly but systematically improve anti-tumor immunity elicited by IL-12-secreting BMK-16/myc cells. Injection of irradiated B7-1/IL-12+ BMK-16/myc cells generates long-lasting, Th1-type, BMK-16/myc-directed immunity in tumor-resistant mice. These mice display a memory-type, E7-specific, cell-mediated immune response, which is potentially significant for clinical applications.

Wild-type p53 down-regulates transcription from oncogenic human papillomavirus promoters through the epithelial specific enhancer.

High-risk Human Papillomavirus (HPV) E6 and E7 immortalizing oncoproteins are expressed from a promoter tightly regulated by an epithelial specific enhancer. To determine if the p53 tumour suppressor protein can modulate the transcription of these genes, we performed co-transfection experiments with plasmids containing the HPV type 16 or 18 long control regions linked to the chloramphenicol acetyl transferase gene, along with p53 expression vectors. Wild-type, but not mutant, murine or human p53 expression vectors reduced the activity of reporter constructs when co-transfected into HeLa or C33 cell lines. Mutations within the HPV TATA boxes did not significantly alter the levels of p53 repression, suggesting a TATA-independent mechanism. Deletion analyses mapped the p53-responsive domain to the constitutive 230 base pair epithelial specific enhancer. In addition, the enhancer could confer p53-mediated repression when placed upstream of a heterologous promoter.

[Gene therapy: technics, strategy and application]. / Thérapie génique: techniques, stratégies et applications.

The concept of gene therapy extends to all treatments involving modification of cellular genetics. This approach has numerous applications such as the treatment of genetic disorders, cancer and viral diseases. The first of these implies the introduction of a normal gene to replace the function of the defective gene. In the other two, several strategies may lead to a therapeutic effect. The transfer of genes is equally applicable in any disease where the expression of the gene in the particular tissue is more effective than systemic or local treatment with the corresponding protein (for example Dopamine or Tyrosine hydroxylase for Parkinson's Disease). According to its application and to the strategy chosen, therapeutic gene may be transferred, in vitro or in vivo, with the aid of plasmid vectors or recombinant viruses. These vectors may contain targeting systems and/or regulation of the specific expression of the target cell. Some encouraging results have been obtained for different applications in animals and there are numerous clinical studies currently in progress.

Transcriptional activation of several heterologous promoters by the E6 protein of human papillomavirus type 16.

The E6 protein of human papillomavirus type 16 (HPV-16), along with E7, is responsible for the HPV-induced malignant transformation of the cervix. However, the mechanism of this transformation activity is not well understood. We investigated whether the entire E6 protein of HPV-16 could act as an activator of transcription. Experiments in which NIH 3T3 cells were cotransfected with an E6 expression vector together with the reporter chloramphenicol acetyltransferase (CAT) gene linked to various minimal promoters indicated that E6 could activate transcription from a series of viral TATA-containing promoters. Mutations or deletions that affected all upstream regulatory elements present in the thymidine kinase (TK) promoter, such as the GC and CAAT boxes, reduced the level of E6-induced transcription. However, compared with the basal level, these truncated promoters were still activated by E6. Although site-directed mutations of the TATA sequence present in the TK or human immunodeficiency virus long terminal repeat promoters reduced the level of basal transcription, they did not abolish the E6-mediated activation. Moreover, E6 could restore almost completely the full level of wild-type E6-induced transcription as long as the upstream regulatory elements (GC/CAAT in the TK promoter, NF-kappa B in the human immunodeficiency virus long terminal repeat) were intact. This dual interaction of HPV-16 E6 is reminiscent of the activity of a coactivator.

[Effect of wind and temperature on concentrations of Pb in urban air. I. Example of a location situated under the direct influence of intense traffic]. / L'influence du vent et de la temperature sur les concentrations en Pb dans l'air urbain. I. Cas d'un site situe sous l'influence directe du trafic intense.

A simple mathematical relationship has been established between the Pb concentrations in the ambient air in the vicinity of a heavy-traffic road and some meteorological parameters (wind speed and direction, temperature). The application of this relationship permits the interpretation of the variations in concentrations with respect to the time of day and period of the year.

Evaluation of the total Cr-levels in the ambient air in Belgium.

As a part of the general network for the monitoring of heavy metals in the ambient air in Belgium, total Cr-levels were measured at 14 stations distributed over the country from April 1982 until March 1985. The most important statistical results are summarized and discussed. In two regions, Liège and Genk, with important ferrous industries, elevated chromium pollution with important peak values has been detected. In the last five years, a marked increase has been noted for the Liège region, while at the other sites only small changes occurred. The relationship between chromium and the other metals measured in the ambient air is examined and discussed. On the basis of pollution data an attempt of source identification is presented.

Application of linear regressions to the comparison of analytical procedures for the determination of SO2 in ambient air.

Three commonly used analytical methods for the determination of SO2 in ambient air were compared during 10 months at six different sites. The acidimetric method, used in the Sulfur-Black Smoke network, and the FPD method, used in the Belgian Automatic Network for Air Pollution, were compared with the TCM reference method. Several regression methods were used to calculate the relationships between the daily averages obtained by the three measuring techniques. Knowledge of the relative importance of the errors on the different sets of data was a determining factor for the selection of the most suitable regression method. The results show good agreement between the three methods during the field-test period.

A study of the persistencies of SO2 concentrations exceeding limit values in the ambient air of an urban area.

This study of the persistencies of SO2 concentrations takes the parameters of the SO2 frequency distributions as a basis. A scheme is proposed for their calculation which allows the forecast of SO2 pollution episodes.

[Effects of the wind and temperature on the concentrations of sulfur dioxide in the ambient air]. / L'influence du vent et de la température sur les concentrations en dioxyde de soufre dans l'air ambiant.

A simple mathematical relationship has been established between the ambient SO2 concentration and some meteorological parameters (wind speed and direction, temperature). The application of this relationship permits the quantification of the influence of the buildings heating and the long-range transport on the SO2 levels measured.