Fred Rapp

Malignant transformation of hamster embryo fibroblasts following exposure to ultraviolet-irradiated human cytomegalovirus

Following exposure to ultraviolet-irradiated cytomegalovirus, clones of noncontact inhibited hamster embryo fibroblasts were isolated. A continuous cell line (Cx-90-3B) was established from one of these clones which proved oncogenic when inoculated into weanling golden Syrian hamsters. Cytomegalovirus antigens could be demonstrated in the cytoplasm and on the surface of Cx-90-3B cells using human convalescent sera. Furthermore, serum from tumor bearing animals was shown to contain antibody to cytomegalovirus specified antigens. These observations are similar to those previously reported for herpes simplex viruses and represent the first demonstration that human cytomegalovirus has transforming potential in mammalian cells.

Transformation of mammalian cells by DNA-containing viruses following photodynamic inactivation

Abstract Simian papovavirus 40 (SV40) and herpes simplex virus (HSV) types 1 and 2 were nactivated by exposure to fluorescent light after replication in cells pretreated with neutral red. Exposure of hamster embryo fibroblast cells to appropriately inactivated virus yielded clones of cells showing loss of contact inhibition. Cell lines were established from clones arising from “transformation” by all viruses tested. SV40 tumor (T) antigen was detected in the nuclei of the SV40 transformed cells and herpes simplex virus specific antigens were demonstrated in the cytoplasm of both type 1 and type 2 transformed cells. Virus was not recovered from the transformed cells. The results indicate that DNA-containing viruses are able to transform mammalian cells after photodynamic inactivation of infectivity.

NEW SURFACE ANTIGEN IN CELLS TRANSFORMED BY SIMIAN PAPOVAVIRUS SV40.

Summary Hamster cells transformed by papovavirus SV40 in vitro and in vivo possess new surface antigens that can be detected by the indirect immunofluorescent technic. Antibody against the surface antigens of the SV40-transformed cells fail to react with normal cells from various species including the hamster, with the “spontaneously” oncogenic hamster BHK21 cells, or with hamster cells transformed by adenovirus type 12. Inoculation of hamsters with cells not transformed by SV40 did not elicit synthesis of an antibody capable of reacting with the surface antigens of the cells transformed by the papovavirus.

Virus-Induced Intranuclear Antigen in Cells Transformed by Papovavirus SV40.∗

Summary Hamsters bearing virus-free tumors induced by cells transformed in vitro or in vivo by papovavirus SV40 produce circulating antibody capable of reacting with intranuclear antigens synthesized by SV40-transformed cells. The reaction is particulate and does not involve the nucleolus. All cells in transformed cultures, regardless of whether they are of hamster or of human origin, synthesize the antigen. We wish to acknowledge the able technical assistance supplied by Myron Katz.

Induction of cellular DNA synthesis and increased mitotic activity in syrian hamster embryo cells abortively infected with human cytomegalovirus.

The effect of human cytomegalovirus (CMV) on cell DNA synthesis and mitotic activity in hamster embryo fibroblasts was examined. The results indicated that CMV infected cells had increased rates of cell DNA replication and mitotic activity. Detection of the effect of CMV on these two parameters necessitated arrest of cells prior to infection with low serum concentrations. This lowered the background levels of DNA synthesis and cell division so that the effect of virus infection could be detected. The data indicate that cells arrested prior to infection demonstrate increased susceptibility to virus infection. It was also observed that the effect of CMV on both DNA replication and mitotic activity could be enhanced by irradiation with ultraviolet light of the virus prior to infection.

Intracellular branched tubular structures in osteosarcoma. An ultrastructural and serological study

Intracytoplasmic tubular structures, approximately 23 mμ, in diameter, were seen by electron microscopy within endothelial cells, malignant osteoblasts, and lymphocytes of an osteosarcoma. Although similar tubular structures have been seen in many different cells in vivo and in vitro, their presence within endothelial cells of glomeruli in patients with systemic lupus erythematosus prompted the suggestion that they represent measles virus nucleocapsids. Although the morphogenesis of these tubules remains obscure, we have presented evidence that these tubules may form by condensation of intracisternal granular material secreted by the endoplasmic reticulum and probably represent response of the cell to injury by providing it with more structural stability. Measles antibody titers were performed on the sera of the patient and his immediate family, because similar tubules had been equated with measles virus nucleocapsids. Because these antibody titers were all markedly elevated, a comparative ultrastructural study was undertaken between the tubules reported herein and measles virus nucleocapsids. Although the ultrastructural features were superficially similar, their morphology and morphogenesis were different. Thus, we concluded that such tubular structures could not be equated with measles virus nucleocapsids. Several possible reasons for the high measles antibody titer in the sera of the patient and his immediate family are discussed.

Studies of an epstein-barr virus-induced DNA polymerase

Abstract Epithelial/Burkitt hybrid cells (D98/HR-1) typically express the Epstein-Barr-associated nuclear antigen (EBNA). Synthesis of early antigen (EA) and virus capsid antigen (VCA) is repressed. Following treatment with 5-iodo-2′-deoxyuridine (IUdR), however, Epstein-Barr virus (EBV) EA and late virus-specific products, including EBV DNA and complete virions, are induced. This report demonstrates that phosphonoacetic acid inhibits expression of VCA, but has no effect on EA. Cells treated with IUdR were also found to express a new DNA polymerase which was susceptible to stimulation by salt and was not present in uninduced cells. This salt-stimulated DNA polymerase resembles other herpesvirus-induced DNA polymerases in its requirements for maximal activity and its ability to use synthetic templates in DNA synthesis. Data suggest that this DNA polymerase is induced by EBV and is necessary for the productive synthesis of virus-specific DNA.

Antigenic Differences between Isolates of Herpesvirus Type 2

Isolates of herpesvirus type 2 from different geographic areas were examined for antigenic differences using the kinetics of neutralization and 51Cr release tests. Though differences in the kinetics o

Evidence for the Association of Cytomegalovirus with Carcinoma of the Prostate

A human genital isolate of cytomegalovirus is shown to have transformed human embryonic lung cells in vitro. These cells produce tumors when injected into athymic nude mice. Two cell lines derived from tissue from human prostatic carcinoma have survived more than 20 passages in vitro and demonstrate cytomegalovirus-specific membrane antigen. Significant humoral antibody titers against cytomegalovirus have been demonstrated. Cell-mediated lymphocytotoxicity against these transformed cells has been demonstrated in patients with urinary tract tumors. This evidence indicates that an association between cytomegalovirus and human prostatic cancer may be more than coincidental.

Herpes Simplex Virus Latency in Cultured Human Cells Following Treatment with Cytosine Arabinoside

Summary Treatment of human cell cultures infected with herpes simplex virus type 2 (HSV-2) with cytosine arabinoside resulted in the prevention of both virus cytopathology and synthesis of detectable infectious virus. Following removal of the inhibitor infectious HSV-2 reappeared and the cultures were destroyed. However, there was a delay of at least 5 to 6 days following inhibitor removal before infectious virus could be detected. The reappearance of infectious HSV-2 was paralleled by virus cytopathology. The period between the disappearance and reappearance of infectious virus is defined as the latent period. Cultures during this period were as sensitive as control cultures to superinfection with HSV-2 or vesicular stomatitis virus. Infectious centre assays performed with cultures during the latent period indicated that as many as 1 in 800 cells were capable of ultimately synthesizing infectious virus. Attempts to prevent the reappearance of infectious HSV-2 by treating infected cultures with cytosine arabinoside for up to 22 days were unsuccessful, thus indicating that HSV-2 can remain associated with the cells in a non-infectious form for an extended period without being degraded.