Serological Reactions With a Virus Causing Rabbit Papillomas Which Become Cancerous

Abstract

The serum of a rabbit with large cancers resulting from the transplantation of a squamous cell carcinoma that had arisen from a virusinduced papilloma, possessed the power to neutralize the virus, and so too in less degree did that of an animal of the same transplantation series in which a small nodule had developed. The sera of rabbits carrying tar papillomas or the Brown-Pearce carcinoma proved wholly devoid of effect on the virus. The implantation of Brown-Pearce tumor material mixed with virus did not lead to an enduring establishment of the latter in the resulting growths, nor to any immediate changes in their morphological character. The significance of the facts is discussed.

Arthropod Transmission of Rabbit Papillomatosis

“…Many have considered that the virus in domestic rabbit papillomas is in a masked form, not recognizable by the usual techniques (15,16), although demonstrable by serological methods (12,15,17,18). However, the sensitivity of the domestic test animal can be increased by making the skin hyperplastic with methylcholanthrene or a turpentine-acetone mixture so that infectivity of wart suspensions from many domestic rabbits can be demonstrated (5,6).…”

A Distinctive Substance Associated With the Brown-Pearce Rabbit Carcinoma

“…But this negative result may merely mean that the extracted material lacked the capacity to induce neoplasia under the conditions of the tests; it does not preclude the possibility that the active substance may be responsible for the neoplastic activities of the tumor cells under the conditions of its natural association with them. The fact may be recalled in this connection that many papillomas and cancers induced experimentally with the Shope virus in domestic rabbits have failed to yield infectious virus on extraction, yet the virus is known to persist in the papillomas in "masked" form, increasing in amount as the growths enlarge (14), and its presence has been demonstrated by serological means in the two cancers that have been successfully transplanted3 W h e n viewed as a whole, the evidence does not allow one to say whether the serologically active substance of the Brown-Pearce tumor plays any significant part in the activities of the tumor cells. A full understanding of its significance must await the results of further work.…”

The Course of Virus-Induced Rabbit Papillomas as Determined by Virus, Cells, and Host

“…These antibodies neutralize the virus in vitro, yet they do not influence the course of the growths it induces. In some rabbits the growths enlarge progressively although nourished by blood of high antiviral potency, whereas in others in which the antiviral titer of the serum is comparatively low, they dwindle and disappear (3). The living papilloma ceils evidently protect the papilloma virus, as other cells do other viruses (4), and apparently they protect it amply.…”

“…10 months later part of the glycerolated material was weighed, washed briefly in Tyrode's solution, ground with sand and made up to a 5 per cent suspension in Tyrode, and tested for infectiousness, along with 20 other suspensions made from glycerolated papillomas from as many cottontails in which growth had been progressive. All were inoculated into squares of skin on each of 3 normal domestic rabbits, according to a standard technique (3). By the 15th day thereafter, multiple, discrete growths had appeared on 2 of the rabbits where the W.R. 27-N suspension had been inoculated, and by the 19th day on the third rabbit as well.…”