Relationship between feline leukemia virus antigen expression and viral infectivity in blood, bone marrow, and saliva of cats.

Correlation was greater than 90% between feline leukemia virus (FeLV), group-specific antigen (GSA) in leukocytes, and viral infectivity (VI) in serum or plasma from 132 cats infected with either the Rickard strain of FeLV, the Snyder-Theilen strain of feline sarcoma virus, or field strains of FeLV. Detection of GSA in blood cells was at least as sensitive as detection of VI in serum. In 45% of FeLV GSA-positive cats inoculated with FeLV-Rickard strain, VI was detected in saliva. No saliva samples from GSA-negative cats had VI. Sequential bone marrow biopsies from 34 cats inoculated with Snyder-Theilen feline sarcoma virus indicated that the correlation between FeLV GSA in bone marrow cells and blood cells was virtually 100%. FeLV GSA appeared in bone marrow leukocyte precursors 1 week before its appearance in peripheral blood leukocytes in 50% of the cats. The FeLV GSA-positive state was transient (3 to 6 weeks) in 34% of the Snyder-Theilen feline sarcoma virus-inoculated cats.

Detection of low copy human papilloma virus DNA and mRNA in routine paraffin sections of cervix by non-isotopic in situ hybridisation.

In analysing human papilloma virus (HPV) infection of the cervix in formalin fixed paraffin sections by non-isotopic in situ hybridisation two main problems were found: detachment of sections from the glass during hybridisation and probe detection; inadequate sensitivity and inability to assess sensitivity of the in situ procedure. The first problem was investigated by assessing the efficiency of various tissue adhesives individually and in combination. The second problem was addressed by optimising conditions for DNA unmasking, hybridisation, and biotinylated probe detection. Sensitivity of the final in situ procedure developed was assessed by using the detection of pHY2.1 repeats as a built-in control. Extrapolation of data showed that less than 10 copies of HPV DNA can be visualised by these procedures. HPV nucleic acid, mainly in the form of DNA, was detected not only in koilocytic nuclei but also in suprabasal cells in condylomas and CIN lesions. HPV mRNA was also visualised in the cytoplasm (and probably also nuclei) of the same cell types. These non-isotopic in situ procedures give results comparable to those obtained with radiolabelled probes, but they are less time consuming and provide better morphological resolution.

Induction of virus-producing tumours in athymic nude mice by bovine papillomavirus type 4.

Bovine papillomavirus type 4 (BPV-4), the causative agent of alimentary papillomatosis, has been used to infect, in vitro, fragments of palatine mucosa from late term bovine fetuses. These small explants were placed beneath the renal capsule of athymic nude mice where they grew to produce, at first, squamous epithelial cysts containing BPV-4 genomic DNA and, later, papillomas which were morphologically identical to those of cattle and which contained large amounts of replicating virus. The possible utility of this technique in assessing neutralising antibodies in vaccine development is discussed.

Analysis of the transforming functions of bovine papillomavirus type 4.

Bovine papillomavirus type 4 (BPV-4) morphologically transforms primary bovine cells in vitro only in the presence of an activated ras gene. The transformed cells are capable of anchorage-independent growth, but are not immortal and are incapable of inducing tumors in nude mice. BPV-4 does not possess an E6 ORF and failure to induce full transformation may be due to the lack of this gene. Here we report the contribution of individual BPV-4 genes to cell transformation and the effect of adding the E6 ORF of HPV-16 to the system. We show that BPV-4 E7 ORF is responsible for morphological transformation, the E8 ORF is responsible for anchorage-independent growth, and addition of HPV-16 E6 ORF rescues cells from senescence. By immunocytostaining, E7 and E8 have been visualized in transiently transfected cultured cells. E8 is localized in the membranes while E7 is found both in the cytoplasm and in the nucleus.

Transmission of human papillomaviruses from mother to child.

Exfoliated cervical epithelial cells from women 6 weeks postpartum were analyzed for human papillomavirus (HPV) DNA using the polymerase chain reaction, and results were compared with those from buccal mucosal smears from their babies. Eleven mothers had genital genotypes of HPV in their cervical smears, and the children of 8 of these had HPV of the same genotype in buccal mucosal cell samples. Nineteen mothers had no HPV DNA detected in their cervical smears, and 1 of the buccal mucosal cell samples from their children was positive for HPV DNA (p < 0.0001). Contamination of a child's mouth with 'genital' HPV from a mother's cervix appears to occur commonly at birth or in the perinatal period, and to persist for at least 6 weeks. This observation has implications for the epidemiology and management of HPV associated cancer and precancerous conditions in the cervix and the mouth.

[Epstein-Barr virus infection--a lympho- and epitheliotropic infection]. / Die Epstein-Barr-Virus-Infektion--eine lympho- und epitheliotrope Infektion.

Epstein-Barr virus (EBV) has long been thought to be primarily a B-lymphotropic virus. This tropism becomes obvious in the association of the virus with diseases that become manifest in lymphoproliferative conditions, such as acute infectious mononucleosis or endemic Burkitt's lymphoma. In the course of mononucleosis, however, viraemia cannot be detected and B-lymphocytes infected with EBV in vitro produce only small amounts of the virus. In contrast, recent studies document that EBV replicates in the epithelial cells in the mouth, and pronounced secretion of virus can also be detected. Cells of the basal layer of the epithelium can be infected via the EBV-specific CR2 receptor. Upon mitosis of the cells of the basal layer, EBV genome in episomal form is partitioned to the daughter cell. On the other hand, differentiation and maturation of the epithelial cells is paralleled by active virus production. Thus, there is evidence that the epithelial EBV infection is the main factor in the persistence and production of EBV. Accordingly, the EBV infection of epithelial cells which can result in diseases, seems to be the primary process, leading to the infection of B-lymphocytes and then to other diseases. Diseases associated with infection of epithelial cells by EBV and diseases involving B-lymphocytes are discussed with reference to this idea.

Polyoma virus-induced murine odontogenic tumors.

Neonatal mouse pups were injected subcutaneously with polyoma virus to induce odontogenic tumors. This treatment resulted in a spectrum of tumors that arose in organs dependent upon epithelial-mesenchymal interactions for their organogenesis, which included the teeth, salivary glands, thymus, and lacrimal glands. In addition, several odontogenic tumors with a histologic resemblance to ameloblastoma were identified and analyzed with respect to the presence of markers specific for various stages of ameloblast differentiation. Immunodetection analyses of the odontogenic tumors identified fibronectin and laminin, typical of basement membrane organization during early tooth organogenesis. These same tumors failed to express amelogenin, a gene whose expression is limited to differentiated ameloblasts. In contrast, a 47 kDa enamelin-like polypeptide was identified with the use of an antienamelin antibody. These data were interpreted to suggest that the polyoma virus truncated the differentiation pathway for these odontogenic tissues at an early stage of their development and retained the expression of basement membrane components and the enamelin-like polypeptides, yet excluded expression of amelogenin gene products. This observation suggests that polyoma viral transformation may dysregulate odontogenic tissue interactions and produce tumors composed of cells arrested at a specific stage in their development.

Epstein-Barr virus and jaw tumors in North Nigeria.

Nigerian patients with tumors of the jaw were compared with controls in respect of antibodies to the viral capsid antigens of Epstein-Barr Virus (EBV) and of total immunoglobulin levels. Immunoglobulin levels did not differ between patients and controls but increased two weeks postsurgery. Immunoglobulin A (IgA) antibodies to EBV were detected in a small number of patients, and mean titers of IgG antibodies to EBV were lower in the patient group, indicating a lack of association between EBV and tumor formation. An association was noted between the presence of Hepatitis B surface antigen, and depressed antibody titers to EBV in patients with tumors. Of 78 patients studied, 12% were Hepatitis B surface antigen positive.

Detection of BK virus DNA in nasopharyngeal aspirates from children with respiratory infections but not in saliva from immunodeficient and immunocompetent adult patients.

Our understanding of important stages in the pathogenesis of the human polyomavirus BK virus (BKV) and JC virus (JCV) infections is limited. In this context, nasopharyngeal aspirates from 201 children with respiratory diseases and saliva from 60 human immunodeficiency virus type 1-infected adults and 10 healthy adult controls were collected and analyzed for the presence of BKV and JCV DNA by PCR. Neither BKV nor JCV DNA was detected in the saliva specimens. We demonstrated BKV DNA, but no infectious BKV, in 2 of 201 nasopharyngeal aspirates. Each sample contained one unique rearranged noncoding control region variant of BKV. The results indicate that (i) BKV and JCV are not regularly associated with respiratory infections in children requiring hospitalization, (ii) nasopharyngeal cells are not an important site for primary replication of human polyomavirus BKV and JCV, and (iii) the salivary glands and oropharyngeal cells seem not to be involved in BKV and JCV persistence. We propose that for the polyomaviruses BKV and JCV the alimentary tract should be considered as a portal of entrance to the human organism.

Relationship of viral infection to malignancies.

The epidemiologic features and the biologic mechanisms of the oral tumor viruses have been clarified during the period under review. The use of more sensitive detection methods has confirmed that the prevalence of papillomaviruses in the mouth in patients with various lesions, as well as in healthy individuals, is high. Mechanisms by which papillomaviruses are regulated by cells and by which they may control cell behavior have been described. Herpes simplex virus has been shown to induce a variety of mutations in cells. Human herpesvirus type 6 has been found in oral tissues of a number of healthy individuals, and the virus was shown to be capable of transforming cells to a malignant phenotype. Hairy leukoplakia was found in other individuals who were not infected with the human immunodeficiency virus, and a new animal model for hairy leukoplakia was introduced. Because of the high frequency of oral viruses in nondiseased individuals, more attention must be paid to their mechanisms of action before it will be possible to define the role of viruses in oral malignancies.

Identification of genital tract papillomaviruses HPV-6 and HPV-16 in warts of the oral cavity.

Warty lesions of the oral cavity were examined for etiologic association with genital tract papillomaviruses HPV-6, HPV-11, and HPV-16. DNAs extracted from ten oral biopsies were screened for HPV genomic sequences by Southern transfer hybridization with 32P-labeled viral DNA probes. Nonstringent hybridization with an HPV-6 probe revealed papillomavirus DNA sequences in four of seven tissues with histologic evidence of papillomatosis, in none of two tissues without histologic evidence of papillomatosis, and in one tissue that was not examined by histology. Stringent hybridization tests with HPV-6 and HPV-16 probes identified the genome in one tissue as being HPV-16, in a second tissue as being HPV-6 subtype a, and in a third tissue as HPV-6 (subtype unidentified); papillomavirus DNA sequences in two tissues are as yet not identified. An additional case of HPV-6 or HPV-11 related oral cavity lesion was diagnosed by in situ hybridization of paraffin sections with a 35S-labeled, mixed HPV-6 + HPV-11 probe. The hybridization in the positive section was extensive and confined to epithelial nuclei. The oral lesions associated with genital tract papillomaviruses were asymptomatic, multiple or single, and were located in different parts of the oral cavity, for example, on the gingivae, on the tongue, on the lip, on the tonsillar pillar, and on the floor of the mouth.

The epithelial neoplasm observed in the cultured coho salmon, Oncorhynchus kisutch.

The epithelial neoplasms were observed on the mouth of the cultured coho salmon, Oncorhynchus kisutch. Histopathologically, the tumors were formed to be proliferative epithelial cells, but no change was observed in other organs. The virus from this tumor was isolated in RTG-2 and CHSE-214 cells and developed the cytopathic effect which characterized to be the formation of syncytia and the migration of chromatin. This virus was neutralized with anti-Oncorhynchus masou virus (OMV) rabbit serum.