Comparative studies of transformed hamster cells by Herpesvirus hominis types 1 and 2.

Hamster embryo cells transformed by Herpesvirus Type 2 (HSV-2) virus (two separate cell lines) and by HSV-1 virus (one cell line) were inoculated into hamsters. The morphological appearance of tumours was studied by both light and electron microscopy, and the results compared to similar studies of tumours induced by SV40 virus. The tumours were also tested for immunogenicity, and for susceptibility to contact suppression with BCG. The results indicated that the tumours induced by inoculation of HSV-transformed cells were distinct from those of other DNA viruses; that the two cell lines transformed by HSV-2 were very similar but distinct from the cell line transformed by HSV-1; that all 3 HSV tumour cell lines were weakly immunogenic, and 2 were susceptible to contact inhibition with BCG. The relevance of the morphological and immunogenic properties of the animal tumour is discussed with relation to the possible importance of the findings to human malignant disease.

Tumorgenicity of herpesvirus hominis type 2-transformed cells (line 333-8-9) in adult hamsters.

Inoculation of adult hamsters with greater than 1.5 X 10(2) Herpesvirus type 2 (HSV-2) transformed hamster embryo fibroblasts induced rapidly growing tumours at the site of inoculation, in more than 50 per cent of animals. The tumours were examined by light and electron microscopy, and were histologically anaplastic fibrosarcomas. Lung metastases were frequently found in tumour-bearing animals; these were usually only seen microscopically, and were cytologically similar to the primary tumours. The nature of tumour development showed similarities with naturally occurring tumours of man, and HSV-2 tumour is probably a better model of human cancer than other virus-induced tumours studied in the past.