Ronald Duff

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

Immunologic Manipulation of Metastases due to Herpesvirus Transformed Cells

Herpes simplex virus type 1 (HSV-1), type 2 (HSV-2), and simian virus 40 (SV40) fail to induce immunity in weanling Syrian hamsters to transplant of hamster cells transformed by HSV-2. However, the development of metastatic tumors is markedly enhanced by prior immunization with HSV-1. Immunization with SV40, ultraviolet-irradiated tumor cells, or ultraviolet-irradiated normal hamster embryo cells inhibits the development of metastases. The HSV-hamster system appears a good one for the study of development, prevention, and control of metastases by mammalian cells transformed by a common human virus.

Oncogenic conversion of normal cells by inactivated herpes simplex viruses

There are two genetically distinct subtypes of herpes simplex virus (HSV) endemic in human populations. Both Type 1 and Type 2 viruses induce several pathologic conditions and have now been associated with a variety of human neoplasias by serologic techniques. Support for the oncogenic potential of these viruses derives from several observations: 1) Seroepidemiologic studies have consistently linked an increased incidence of neutralizing antibodies to HSV‐2 with the presence of cervical carcinoma; 2) The presence of antibody to early (non‐virion) herpesvirus antigens has been reported in patients with invasive cervical carcinoma and eight other neoplasias of the oral and genital area, but not in normal cases; 3) The presence of HSV‐2 antigens in exfoliating cervical carcinoma cells, recovery of a virus identified immunologically as HSV‐2 from virus‐free tumor cells maintained in culture, and the detection of a fragment of the HSV‐2 genome in cells from one cervical tumor associates the virus with chromosomes of neoplastic cells; 4) Equally significant are the multiple demonstrations that HSV‐1 and HSV‐2 can transform hamster, mouse, and human cells in culture to cells that can then establish permanent lines, contain virus nucleic acids, and express virus markers. These cells may be malignant when transplanted into histocompatible hosts. Taken together, these observations strongly associate herpes simplex viruses with a variety of human cancers and urge further study to resolve their role in etiology.

Characteristics of Herpes Simplex Virus Resistance to Disodium Phosphonoacetate

Herpes simplex virus (HSV), which was partially resistant to the inhibitory effect of disodium phosphonoacetate (PAA), could be recovered following four virus passages in the presence of 100 microgram/ml PAA. Resistant strains were isolated from both HSV type 1 and HSV type 2. Virus resistance to PAA was not complete, and in most isolations a significant proportion of the virus stock remained susceptible to the drug. Resistance was shown to be heritable and persisted through virus passage and cloning experiments. PAA inhibited the replication of virus-specific DNA in sensitive strains of HSV but not in resistant strains of HSV. In vitro experiments directly demonstrated that PAA inhibited the activity of the virus-specific DNA polymerase 10 times more effectively in PAA-susceptible HSV than in PAA-resistant HSV. The treatment of HSV-infected mice with high levels of PAA did not induce the formation of resistant virus strains.

Sialidase activity of oncogenic cells transformed by herpes simplex virus

Abstract Sialidase in normal nononcogenic hamster embryo fibroblasts was not active toward added disialo- and trisialoganglioside, but all transformed lines of hamster embryo fibroblasts studied had sialidase active toward added ganglioside substrate. The levels of exogenous sialidase activity suggested a parallel trend in the amount of this activity and the degree of oncogenicity of the transformed cells. Exogenous sialidase activity in a weakly oncogenic cell line was found to increase after passage of the cells into hamsters and isolation and cell culture of the resulting tumors which gave rise to a cell line of relatively high oncogenicity.

Characteristics of the Release of Measles Virus from Latently Infected Cells after Co-Cultivation with BSC-1 Cells

The events during the release of measles virus from latently infected hamster cells after co-cultivation with BSC-1 cells were studied by immunofluorescence and electron microscopy techniques. Before co-cultivation, measles virus antigens (nucleocapsid) were distributed in an apparently random fashion throughout the cytoplasm. Six hours after co-cultivation with BSC-1 cells, the measles virus nucleocapsid became aggregated in close proximity to the nuclear membrane. These antigens then diffused towards the cell periphery, and progeny virus was observed budding from the cell surface by 16 h after co-cultivation. Fusion of the BSC-1 cells to the latently infected hamster cells was necessary for virus release to occur, and an intact, viable BSC-1 cell was also required. A possible mechanism for the block of virus replication in the latently infected cells is discussed.

Resistance of Hamster Cells Transformed by Herpes Simplex Virus Type 2 to Superinfection by Herpes Simplex Viruses

Cultures of hamster embryo fibroblasts originally trans formed in vitro by herpes simplex virus (HSV) type 2 previously irradiated with ultraviolet light were resistant to superinfection by HSV-1 and HSV-2. The degree of resistance was dependent upon the concentration of the superinfecting virus. At an MOI of 1.0 infectious virus particle per cell, significant virus replication occurred. At an MOI of 0.001 per cell, little or no virus replication was detected. In normal hamster embryo fibroblasts, virus replicated when either high or low MOI were used. Early events in the virus-replicative cycle were found to proceed normally. The results suggest that HSV can initiate and complete the infectious cycle in a limited number of herpes-transformed cells, a finding similar to that observed for Epstein-Barr herpesvirus systems.

Quantitative transformation of primate cells by PARA (defective SV40)-adenovirus type 7.

A quantitativein vitro assay for the transformation of primate cells by PARA (defective SV 40)-adenovirus type 7 has been developed which allows comparison of the suceptibility of primate and rodent cells to PARA transformation. Transformation by PARA followed one-hit kinetics with a ratio of 12,500 plaque forming units of virus for each focus forming unit in the most efficient primate system tested. The ratio of plaque forming units to focus forming units in hamster embryo fibroblasts using the same virus stock was 2500∶1. The ability to quantitatively determine the transforming capacity of PARA depended upon the strain of PARA-adenovirus 7 employed and the cell type transformed. Single foci were isolated and characterized with respect to morphology and antigenicity. All were composed of cells with a morphology consistent with SV 40 transformation and contained SV 40-induced antigenic determinants. None contained detectable adeno virus specific antigens. Transformation did not alter the characteristic of the cells with respect to the ability to support the replication of various viruses.