Larry E. Bockstahler

Ultraviolet light enhanced reactivation of a mammalian virus

Abstract When CV-1 mammalian cells are lightly UV-irradiated before infection with UV-irradiated herpes simplex virus, an increase in survival (UV-reactivation) of this virus is observed. The doses of UV to the cells necessary for maximizing UV-reactivation were a factor of about 10 lower than those previously reported for bacteriophage-bacteria systems.

RADIATION ENHANCED REACTIVATION OF NUCLEAR REPLICATING MAMMALIAN VIRUSES

Abstract— When CV‐1 monkey kidney cells were UV‐irradiated (0–18 J/m2) or X‐irradiated (0–10krads) before infection with UV‐irradiated simian adenovirus 7 (SA7) or simian virus 40 (SV40), increases in the infectivity of these nuclear replicating viruses as measured by plaque formation were observed. These radiation enhanced reactivations, UV enhanced reactivation (UVER) and X‐ray enhanced reactivation (X‐ray ER), occurred both when virus infection immediately followed irradiation of the cells (except for X‐ray ER with SA7) and when virus infection was delayed until 3–5 days after cell irradiation. While there was little difference in the levels of reactivation of UV‐irradiated SV40 between immediate and delayed infection, delayed infection resulted in higher levels of reactivation of SA7. X‐ray enhanced reactivation of UV‐irradiated Herpes simplex virus persisted for several days but did not increase. Thus, X‐ray enhanced and UV enhanced reactivations of these mammalian viruses were relatively long‐lived effects. Essentially no UVER or X‐ray ER was found in CV‐1 cells for either immediate or delayed infection with UV‐irradiated vaccinia virus or poliovirus, both of which replicate in the cell cytoplasm. These results suggest UVER and X‐ray ER in mammalian cells may be restricted to viruses which are replicated in the cell nucleus.

Ultraviolet enhanced reactivation of a human virus: Effect of delayed infection

The ability of UV-irradiated herpes simplex virus to form plaques was examined in monolayers of CV-1 monkey kidney cells preexposed to UV radiation at different intervals before virus assay. From analysis of UV reactivation (Weigle reactivation) curves it was found that as the interval between cell UV irradiation (0-20 J/m2) and initiation of the virus assay was increased over a period of five days, (1) the capacity of the cells to support unirradiated virus plaque formation, which was decreased immediately following UV exposure to the monolayers, increased and returned to approximately normal levels within five days, and (2) at five days an exponential increase was observed in the relative plaque formation of irradiated virus as a function of UV fluence to the monolayers. For high UV fluence (20 J/m2) to the cells, the relative plaque formation by the UV-irradiated virus at five days was about 10-fold higher than that obtained from assay on unirradiated cells. This enhancement in plaque formation is interpreted as a delayed expression of Weigle reactivation. The amount of enhancement resulting from this delayed reactivation was several fold greater than that produced by the Weigle reactivation which occurred when irradiated herpes virus was assayed immediately following cell irradiation.

Induction and enhanced reactivation of mammalian viruses by light.

Publisher Summary The chapter discusses the certain studies that concern the induction and enhanced reactivation of DNA-containing mammalian viruses by light. The chapter also discusses the enhanced reactivation and induction of mammalian viruses because (a) they represent potential mammalian “SOS” functions, (b) they may be associated with mammalian cell oncogenic transformation; and (c) to use viruses as tools to study phenomena related to DNA repair. Response curves were obtained by determining induced SV40 infectivity for different values of light exposure and dye concentration. The induction was clearly a function of both these parameters, which gave partial justification for calling the effect a photodynamic induction. The maximum levels of induction found for each response curve were similar in amount and represented about a thousandfold increase above spontaneous background levels observed with untreated cells. The results suggest that photodynamic treatment also reduces the capacity of the cells to support the growth of induced virus. The ultraviolet-enhanced reactivation of herpes simplex virus in host monkey kidney cells is described.

Photodynamic therapy for herpes simplex: a critical review.

Abstract The purpose of this review is to summarize available experimental and clinical data concerning benefits and potential risks of photodynamic therapy for oral and genital herpes simplex virus infections. Since such infections are a source of discomfort and pain, and since recent evidence links the virus itself with carcinogenesis, clinicians have felt an increased need for more effective therapy for herpesvirus infections. In 1973 a human clinical therapeutic procedure based on photodynamic inactivation was developed. The treatment consists of applying a photosensitizing dye to herpesvirus lesions and then exposing them to visible light. A number of human clinical trials have been completed; some of these show reduction of herpesvirus infectivity, whereas others question the efficacy of the procedure. Data from a number of in vitro virus-host cell studies suggest the procedure may be potentially carcinogenic and therefore clinically hazardous. Thus a controversy exists concerning further use of the treatment. This review gives the reader a basis for understanding the controversy and included basic principles of photodynamic inactivation, medical aspects of herpesvirus infections, development of the therapeutic procedure, results of clinical studies, and results of in vitro studies which indicate potential long-term side effects.

Radiation enhanced reactivation of herpes simplex virus: Effect of caffeine

Ultaviolet enhanced (Weigle) reactivation of UV-irradiated herpes simplex virus in UV-irradiated CV-1 monkey kidney cell monolayers was decreased by caffeine. X-ray enhanced reactivation of UV-irradiated virus in X-irradiated monolayers (X-ray reactivation) and UV- or X-ray-inactivated capacity of the cells to support unirradiated virus plaque formation were unaffected by caffeine. The results suggest that a caffeine-sensitive process is necessary for the expression of Weigle reactivation for herpes virus. Since cafeine did not significantly affect X-ray reactivation, different mechanisms may be responsible for the expression of Weigle reactivation and X-ray reactivation.

Radiation-Enhanced Survival of a Human Virus in Normal and Malignant Rat Cells

Summary The repair phenomena of host-cell reactivation (HCR), uv reactivation (UVR) and X-ray reactivation (X-ray R) were studied in normal embryonic (OMRE) and malignant (RMT) rat cells of the same strain by examining the survival of uvirradiated herpes simplex virus (HV-1). Experiments indicated that HCR was present to the same extent in both OMRE and RMT cells as evidenced by similar e -1 values for both components of the virus survival curve as well as similar extrapolation numbers for the resistant component. UVR and X-ray R were demonstrated in RMT cells as indicated by enhanced survival of irradiated virus; however, both of these repair processes were absent in OMRE cells. The amount of UVR in RMT cells increased with virus uv dose and cell uv exposure. It was evident that HCR and radiation enhanced reactivation (UVR and X-ray R) may operate independently in these mammalian virus–host cell systems. We thank Lynda Kramer and Wah Lee for assistance in X-irradiation of cells and C. David Lytle, F. Alan Andersen, and Thomas J. Withrow for helpful discussions and critical review of the manuscript.

Distribution of HIV genomic DNA in brains of AIDS patients

BACKGROUND Data concerning the distribution of HIV in the brains of AIDS patients at different stages of viral infection might contribute towards: (1) understanding the route(s) of HIV entry into the brain and virus dissemination within the brain and (2) establishing a possible correlation between the extent of CNS damage and the distribution of virus in AIDS brains. OBJECTIVE To determine the distribution of HIV-1 genomic DNA within the brains of three deceased AIDS patients by polymerase chain reaction (PCR). STUDY DESIGN The brains of three deceased AIDS patients were examined. Two brains had limited neuropathologic findings (brains I and II), and one brain (brain III) showed primary HIV-specific neuropathologic damage. Tissues were taken from different locations within each brain, and high molecular weight DNA isolated from the tissues was assessed for HIV-1 genomic DNA by PCR. RESULTS HIV-1 genomic DNA was found in all three brains, but the amount was low: order of magnitude of 1 viral genome per 1,000 cells. Multiple PCR analyses of DNA from brain I showed that the viral genomic DNA in this brain was non-uniformly distributed; only samples taken from the brainstem were clearly positive for HIV-1. HIV-1 genomic DNA in brain II was found in portions of the lower and upper hemispheres. All but one of the brain III samples were clearly positive for HIV-1, and they had been taken from locations spread throughout this brain. CONCLUSIONS Our results suggest that in early or latent stages of HIV-infection of the brain, viral genomic DNA is localized at restricted regions. At later stages this DNA is distributed more uniformly throughout the brain. Our data are compatible with the concept of rare infection events followed by viral spreading within brain tissues.

INDUCTION OF ONCOGENIC VIRUSES BY LIGHT

Cells of many animal species contain integrated viral genetic information which exists in a covert, unexpressed form. Such endogenous viral genetic information is thought to be regulated by processes affecting the host cell genes. Although normally repressed, this information may be expressed after exposure of the cells to radiation or a variety of other environmental factors. Viral induction results in release of infectious virus and/or expression of viral gene products. Inducible mammalian viruses include both RNA-containing and DNA-containing viruses, some of which have been demonstrated to be oncogenic or associated with oncogenesis. Results obtained from virus induction studies may contribute to: ( I ) our understanding of the cellular control of gene expression; (2) the establishment of possible associations between cellular DNA repair and induction processes; and (3) the determination of possible relationships between the induction of viruses and oncogenesis. In this brief review attention will be focused on in oitro oncogenic virus induction by light radiation or light plus photosensitizing chemicals. Literature published up until May, 1979, will be covered. Since this is the first Yearly Review on mammalian virus induction, we shall cover some necessary background information. For further background information on virus induction the reader is referred to several recent comprehensive reviews [5 , 26,273.