P. Monini

Latent BK virus infection and Kaposi's sarcoma pathogenesis

We have analyzed by PCR skin lesions from classic, endemic and AIDS‐related Kaposis sarcoma (KS), as well as from KS‐derived cell lines, the presence of ubiquitous transforming viruses. BK virus (BKV), a transforming human papovavirus which has been associated with human tumors, was detected in 100% of KS skin lesions and 75% of KS cell lines. KS specimens contained a full‐length, intact BKV early region, but minor rearrangements were observed in some tumors. BKV was also detected with a high prevalence (57–67%) in genital tissues and sperm, thus fulfilling the role of a sexually transmitted agent in KS. The closely related JC virus (JCV), which has never been associated with human malignancies, was present in 11–20% of KS specimens and was detected with a low prevalence (0–21%) in genital tissues and sperm. Simian virus 40 (SV40) was not detected in any KS lesions. Herpes simplex virus (HSV) DNA sequences were detected in 20–25% of KS lesions. Malignant human papillomavirus (HPV) types 16 and 11 were detected in KS specimens with a similar prevalence of 11–83%, suggesting that the presence of HPV‐transforming sequences is not a specific trait of HPV interaction with KS tissue. Furthermore, JCV, SV40, HSV and HPV DNA sequences were not detected in KS cell lines, suggesting that these viruses are not associated to KS neoplastic cells in KS tissue. KS cell lines were also negative for DNA sequences of KS‐HV, the novel herpesvirus detected in primary KS lesions. The constant association of BKV DNA with KS lesions and KS cell lines suggests that BKV‐transforming functions may participate in the development of KS.

Human papillomavirus type 16 DNA in genital tumours: a pathological and molecular analysis.

The presence of human papillomavirus type 16 (HPV16) DNA in 34 genital tract tumours of Italian female patients was investigated by Southern blot hybridization in high stringency conditions. HPV16 DNA was detected in 16 neoplasias, including cervical invasive and intraepithelial lesions as well as vulvar intraepithelial neoplasias and, to a lesser extent, vulvar invasive carcinomas. Appropriate control tissues included in the study were negative. The data suggest that integration of viral DNA had occurred in most tumours, both in invasive and in intraepithelial lesions. HPV16 variants or defective genomes, lacking the BamHI restriction site, were detected in three tumours.

Association of BK and JC Human Polyomaviruses and SV40 with Human Tumors

The human polyomaviruses BK (BKV) and JC (JCV) are ubiquitous in human populations and have a worldwide distribution.(1) They are oncogenic in rodents and monkeys and transform cells in vitro to a neoplastic phenotype. For all these reasons, BKV and JCV have been considered possible candidates in the etiology of human tumors. Association of BKV, but not of JCV, with human tumors has been described, although a formal proof for an etiological role of BKV in human oncogenesis is still lacking. SV40, which is not a ubiquitous human virus, has also been sporadically detected in human tumors. In this chapter, we consider their general characteristics, the natural history of infection, experimental transformation and oncogenicity by BKV and JCV, as well as the evidence linking BKV, JCV, and SV40 to human neoplasia.

Chimeric BK Virus DNA Episomes in a Papillary Urothelial Bladder Carcinoma

BK virus (BKV) DNA sequences were identified in a papillary urothelial bladder carcinoma by Southern blot hybridization. The carcinoma contained both integrated and extrachromosomal DNA. Integrated sequences had a clonal restriction pattern, suggesting that BKV was integrated at some early stage of neoplastic initiation or progression. Viral episomes consisted of a population of covalent polymers based on a high-molecular-weight DNA unit, about 11-12 kb in size. DNA sequences non-homologous to the BKV genome were encompassed within DNA episomes, suggestive of acquisition of cellular sequences by viral DNA replication at the integration site. Extrachromosomal, chimeric DNA molecules were present at an average level of about 50 copies per cell, but their size, apparently incompatible with viral assembly, showed that BKV productive infection was impaired. The data suggest that infected cells underwent reversible changes affecting autonomous BKV DNA replication.

Impact of sexual habits on the clinical evaluation of male HPV infection

A series of 199 male regular sexual partners of women attending an STD clinic for the examination and treatment of HPV-associated diseases was examined by peniscopy, surgical biopsy and nucleic acid hybridization for the presence of clinical, histological and molecular markers pathognomic of HPV infection. There was a 100% correlation between condylomata acuminata and detection of HPV type 6 or 11 DNA. Papillary lesions displayed neither histological signs of HPV infection, nor did they harbor HPV DNA (viral types 6, 11, 16, 18, 33) while 44.9% (22/49) of acetowhite epithelia showed HPV-suggestive histological changes. Of the 19 analysed for HPV DNA, 15.8% (3/19) harbored HPV 6/11 and 16 DNA. Regular male and female sexual partners did not always harbor the same HPV types, showing that latent or occult infection and the sexual habits of each individual play an important role in the clinical manifestations of HPV infection observed in sexual couples. The present data show that: i) the likelihood of developing a clinical HPV lesion was affected, to a large extent, by the previous sexual history and habits in the partners of women with flat condylomata, while partners of women with condylomata acuminata or CINs displayed a higher correlation with the current state of infection in their regular partner; ii) despite the assessed infective state of their consorts, men with a low lifetime number of sexual partners seldom displayed HPV-associated acetowhitening. Prevalence of such lesions, however, increased significantly with an increase in the total number of sexual partners; iii) clinical assessment and evaluation of HPV-risk for inconspicuous penile lesions in the male partner should be carried out not only on the basis of clinical and peniscopic appearance, but also considering the current state of infection in the regular partner and the sexual history and habits of each individual.

Episomal HPV 16 DNA isolated from a cervical carcinoma presents a partial duplication of the early region

An invasive cervical carcinoma was found to harbor an episomal variant of human papillomavirus (HPV) type 16 DNA, with a size of about 10.1 kb. A genomic library of the tumor was constructed in bacteriophage lambda and a recombinant phage clone was isolated by screening with HPV 16 probe. Analysis by restriction mapping and Southern hybridization showed that the isolate contained a 2.2 kb duplication of the early region, which included part of E6, all E7 and part of E1 open reading frames. Possible consequences of this duplication for oncogenesis are discussed.

Activation of Eukaryotic Transcriptional Promoters by the Bovine Papillomavirus E1-Replication Factor

It has been suggested that the bovine papillomavirus type 1 E1 replication factor may inhibit E2-conditional gene expression from viral promoter P89. To study the possible role of the E1 protein in gene expression, HeLa cells were transfected with E2-conditional or E2-independent reporter plasmids and with vectors expressing the E1 and E2 open reading frames. The data show that: (i) replication factor E1 stimulates gene expression from a variety of eucaryotic transcriptional promoters; (ii) activation of gene expression by E1 also occurs in the absence of viral activator E2-TA; (iii) expression of a recombinant plasmid containing the human papillomavirus type 18 origin of DNA replication is stimulated, but not repressed, by E1, and (iv) E1-dependent activation of gene expression does not reflect the amplification of transfected plasmids.

Search for HSV DNA in genital, cerebral and labial tumors

DNA sequences homologous to HSV-1 and HSV-2 DNA fragments were searched in 64 genital, 35 labial and 34 cerebral tumors. Southern blot transfers of tumor and control DNAs were hybridized in stringent conditions with 32P labelled probes from HSV-1 and HSV-2 cloned DNA fragments. Specific hybridization to HSV-2 BglII N fragment was observed in six (9.4%) genital tumors. Labial and cerebral tumors did not show hybridization to any of the probes used. The technique employed allowed the detection of 0.1 copies of viral fragments per diploid genome.

Effects of the Passive Transfer of Anti-gB Antibodies in a Rabbit Model of HSV-1 -Induced Keratitis

The effectiveness of passively transferred antibodies directed against the secretory form of herpes simplex virus type 1 (HSV-1) glycoprotein B (gB1-s) was tested in a rabbit model of ocular HSV-1 infection. The animals were passively immunized through the intramuscular injection of a homologous polyclonal anti-gB1-s antiserum at different times from the viral ocular challenge (i.e. at -24, 0, +24 and +48 h from infection). The effects observed in this trial were compared with those obtained in an active immunization trial, in which the animals were vaccinated with gB1-s before the ocular infection with HSV-1 (large variant). The results have shown that passive immunization appears quite effective in prophylactic utilization, whereas it is less effective when performed at 24 or 48 h after inoculation. By contrast, active immunization of rabbits proved to be highly effective both in preventing the development of fatal encephalitis and in reducing the severity of corneal lesions.