Analysis of HPV16, 18, 31, and 35 DNA in pre-invasive and invasive lesions of the uterine cervix.

AIMS: To analyse the physical state of different human papillomavirus (HPV) DNAs in 55 intraepithelial and invasive HPV associated cervical neoplasms. METHODS: Restriction analysis, using a panel of five HPV type specific enzymes, was carried out for each sample; this was followed by Southern blot analysis. RESULTS: Six (25%) of 24 cervical intraepithelial neoplasms had integrated DNA of different HPV types. In contrast, integration was detected in 25 (81%) of 31 cervical carcinomas. Tumour samples revealed differences in the integration profile of HPV16 and the other HPV types. Six (26%) of 23 HPV16 associated cancers contained only episomal DNA. In contrast, all eight tumours containing HPV18, 31, or 35 revealed integrated DNA exclusively. CONCLUSIONS: The results suggest that in advanced cervical intraepithelial neoplasia lesions, a subset of lesions can be identified in which the viral genome is integrated and there is a greater risk of malignant progression. In addition, HPV16 DNA was not present in the integrated form in 26% of tumours, suggesting that integration and subsequent inactivation of the transcriptional regulator, E2, are not essential steps for the development of HPV16 associated carcinoma. In this respect, the behaviour of HPV16 associated tumours is different from HPV18, 31, and 35 associated tumours, where the viral genome is always present in the integrated form.

[Cervical intraepithelial neoplasia (CIN) and human papillomavirus (HPV) infection]. / La neoplasia cervicale intraepiteliale (CIN) e l'infezione da human papillomavirus (HPV).

Many studies have shown a strong correlation between CIN and HPV infection. Molecular biology has allowed identification of types of HPV which seem to be connected, more frequently than others, to dysplastic lesions. Physical state of HPV-genome seems to play an important role in the development of cervical cancer. In this study the HPV-genome has been searched in tissue specimens obtained from 34 women affected by CIN II and III. All patients underwent laser conization. Immediately before treatment, colposcopically directed biopsies of the cervical lesion and of the areas with no colposcopically apparent disease were taken and on these samples, HPV-DNA has been searched, isolated and analysed for HPV types and physical state. Histologic examination on cones showed 6 cases of CIN II (3 with HPV), 24 cases of CIN III (14 with HPV), 1 microinvasive carcinoma and 3 with no residual lesion. Southern blot analysis detected HPV-DNA in 4 cases of CIN II (16.7%) and in 20 cases of CIN III (70.6%). In 50% of CIN II and 85% of CIN III HPV 16 DNA has been found and in the remaining 50% of CIN II and 15% of CIN III HPV 31 DNA has been detected. All CIN II and 14 cases of CIN III showed episomal HPV-DNA. Integrated HPV-DNA has been found in 3 cases of CIN III and the other 3 cases of CIN III showed both integrated and episomal HPV-genome. Integrated form has been noticed only for HPV 16 type. In no case of colposcopically normal tissue has HPV-DNA been found. These data seem to confirm the strong correlation between HPV 16 type, which often has integrated form, and CIN III strengthening the hypothesis of its potential oncogenic action.

A method for measuring microquantities of DNA.

Quantitative analysis of DNA content represents a critical step when only very small amounts of nucleic acids are available. The DNA content of a small RNA-free sample can be measured in a simple and precise way using a two-dimensional approach. DNA samples are spotted on the surface of an agarose gel containing ethidium bromide (EtBr) and the ultraviolet-induced low-light fluorescence emitted by EtBr molecules intercalated into the DNA is evaluated. The high sensitivity and reproducibility of this quantitative method has been obtained using an advanced analysis system capable of distinguishing low-light fluorescent patterns, as in the case of DNA stained with EtBr, from the background. Use of an internal standard is necessary because the intensity of the signal is due to the aperture of camera diaphragm and to gel conditions. Using this two-dimensional analysis system it is possible to obtain rapid and precise quantitation of as little as 2 ng of DNA.

Mouse macrophage clones immortalized by retroviruses are functionally heterogeneous.

Murine macrophage clones were generated from thymus, spleen, brain, and bone marrow by in vitro immortalization with recombinant retroviruses carrying an avian v-myc oncogene. The cloned cell lines express F4/80 molecules, exert phagocytosis, have nonspecific esterase activity, and express class II molecules after interferon gamma activation. The macrophage clones are diploid and their karyotypes have remained stable for greater than 3 years in culture. After the macrophage clones were activated, their pattern of cytokine production was investigated. Functional heterogeneity in cytokine transcription was demonstrated: one of six liposaccharide-activated macrophages was unable to transcribe interleukin 1 alpha, whereas all of the liposaccharide-activated clones were able to transcribe tumor necrosis factor alpha. Interleukin 6 production was detected in three of six clones. The production of nitrite and tumor necrosis factor alpha as effector molecules of cytotoxicity was detected in all clones, thus showing that a single macrophage can exert more than one cytotoxic mechanism. The results indicate that immortalized and cloned macrophages have a differentially regulated expression of cytokine genes, adding further evidence for the existence of functional heterogeneity among cloned macrophages. This heterogeneity seems to derive from differentiation-related mechanisms rather than from external constraints.

Retroviral transduction of protein kinase C-gamma into cytotoxic T lymphocyte clones leads to immortalization with retention of specific function.

The molecular pathways that are responsible for delivering the proliferative signals from the cell surface to the nucleus in T lymphocytes are still unresolved, but recent data implicates protein kinase C (PKC) involvement in the TCR signaling pathway. To further address the role of PKC in T cell activation, the effects of high level expression of the PKC-gamma isoenzyme in murine CTL clones were examined. Unlike the parental cells that required periodic Ag stimulation for cell activation and growth, cells expressing a retrovirally transduced PKC-gamma gene propagated in culture independent of the need for Ag stimulation, although maintaining identical functional specificity to the parental CTL. Constitutive PKC-gamma expression may therefore mimic physiologic PKC activation, thereby abrogating the requirement for TCR-Ag interaction in T cell activation.

Cellular sources and effects of tumor necrosis factor-alpha on pituitary cells and in the central nervous system.

Cytokine-mediated communication between the immune system and the nervous system has been shown in the past few years. The precise cellular sources of these molecules in the brain is still a controversial issue. We have thus immortalized primary cell cultures from mouse embryonic brains to analyze cloned cells involved in cytokine production. The cell clones obtained were identified as microglial cells and shown to produce several monokines. Among these, TNF alpha was detected by molecular analysis and cytotoxicity assays and shown to be expressed by microglial cells, after activation with LPS. Surprisingly, the TNF alpha-mediated cytotoxic activity, which was neutralized by specific antisera, was not detected in the cell supernatants but was mediated through cell-to-cell contact. Using antibodies to TNF alpha in FACS analysis, specific cell membrane staining on live microglial cells was shown. The results suggest that in the brain the form of TNF alpha detectable by standard procedures is the cell bound form and not the most common form, secreted TNF alpha. In addition, the effects of recombinant TNF alpha in vitro and in vivo were evaluated. In vitro, rTNF alpha stimulated beta-endorphin, GH, and PRL release from cultured cells prepared from rat anterior pituitary glands. In vivo, the administration of rTNF alpha to rats was able to modify analgesic responses. The concomitant administration of naloxone, an opiate receptor antagonist, or monoclonal anti-IL-1 antibody decreased the analgesic effects induced by rTNF alpha. This indicates that the analgesic effect might not be mediated directly by rTNF alpha but by other mediators, whose action is under the control of TNF alpha.