scholarly journals THE DETECTION OF A "MASKED" VIRUS (THE SHOPE PAPILLOMA VIRUS) BY MEANS OF IMMUNIZATION

1941 ◽  
Vol 74 (4) ◽  
pp. 321-344 ◽  
Author(s):  
John G. Kidd

A study has been made of the immunization procedure described by Shope, with particular reference to the detection of "masked" papilloma virus by means of it. Papilloma extracts were frequently encountered which, though non-pathogenic, elicited the specific antiviral antibody and induced resistance to the virus upon injection intraperitoneally into normal rabbits. The results of the immunization experiments were often complicated, however, by the effects of extravasated antibody, which had accumulated in various amounts in many of the papillomas and was consequently present in extracts of them together with "masked" virus. The extravasated antibody was often sufficient to render extracts of domestic rabbit papillomas non-antigenic; and sometimes, when present in excess, its passive transfer conferred resistance to reinfection with the virus. The conclusion seems warranted that only positive immunization findings can be interpreted with certainty. Negative results provide no decisive evidence as to whether "masked" virus is or is not present in the injected material, unless the amount of extravasated antibody also present is known. The findings may have a bearing on the negative outcome of immunization experiments with extracts of the cancers deriving from the natural papillomas of cottontails. Crude suspensions of domestic rabbit papillomas, which contain little or no virus demonstrable by ordinary methods, are far less antigenic than extracts of the natural growths of wild rabbits, which contain virus in quantity. In explanation of the finding the possibility seems worthy of attention that domestic rabbit papillomas may contain much less virus than the growths of cotton tails, the natural hosts of the virus.

1957 ◽  
Vol 106 (4) ◽  
pp. 555-562 ◽  
Author(s):  
Wilbur Fiske Noyes ◽  
Robert C. Mellors

The results obtained by a fluorescent antibody study of the Shope papilloma virus in papillomas of the wild and domestic rabbit are presented. In the wild rabbit papillomas the viral antigens occurred exclusively in the nucleus and were present in the differentiating cells of the keratohyaline layers and in the keratinized layers. The antigens were not present in the deeper proliferating epithelial cells of the papillomas. The Shope viral antigens were present in very minute amounts in papillomas of the domestic rabbit, as compared with papillomas of the wild rabbit, and were only detected in the superficial keratinized layers. It is postulated that virus is present in the nuclei of the proliferating cells of the papillomas of the wild and domestic rabbit but exists there in an early stage of development, consisting mainly of nucleic acid and deficient in protein, therefore non-antigenic and not demonstrable by fluorescent antibody. The nucleic acid moiety of the virus may be infective, and the protein component may provide immunologic specificity and serve to preserve transmissibility. The protein-deficient virus can be referred to as masked virus.


1961 ◽  
Vol 114 (4) ◽  
pp. 485-500 ◽  
Author(s):  
Yohei Ito ◽  
Charles A. Evans

A deoxyribonucleic acid preparation which showed infectivity and tumorigenic activity in domestic rabbits was isolated from the papillomatous tissue of wild cottontail rabbits by phenolic deproteinization procedure. The activity of the preparation could be completely abolished by its exposure to a minute amount (0.02 µg/ml) of DNAase. Antisera against Shope papilloma virus did not block the tumorigenic activity of the preparation, and trypsin and chymotrypsin had no effect on it. The extraction with phenol of a partially purified virus preparation also yielded extracts with tumorigenic potency. Extracts obtained from the domestic rabbit papilloma and submitted to phenolic deproteinization also proved infective and tumorigenic in rabbits of this sort, although the level of "tumorigenicity" was much lower than that of the cottontail preparations. Tests for intact virus, carried out with half of the extracts yielded wholly negative findings.


1941 ◽  
Vol 73 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Thorolf Packalén

By excising after varying intervals the site of inoculation of the rabbit skin injected intracutaneously with the Shope papilloma virus and titrating its virus content, it has been shown that demonstrable active virus disappears from the skin within approximately 24 hours. The disappearance of most of the virus within such a short time as 15 to 60 minutes makes a transportation of virus from the site of inoculation as a responsible factor unlikely. The rate of disappearance seems to be the same both in the domestic and in the cottontail rabbit.


1963 ◽  
Vol 117 (3) ◽  
pp. 521-542 ◽  
Author(s):  
Stanfield Rogers ◽  
Margaret Moore

These studies make plain that the Shope papilloma virus induces the production of an arginase in rabbit squamous epithelium, and provide evidence that the information for the synthesis of the enzyme is derived from the virus rather than the rabbit. This form of induction is therefore different from that brought about by chemicals such as galactosides (36). Striking differences were shown between the physiochemical properties of Shope virus-induced arginase and other arginases of domestic and Kansas cottontail rabbits. The absence of a requirement for manganese suggests the mechanism of splitting off urea from arginine by papilloma arginase probably differs from that of previously described arginases. These findings (particularly the experiments in which it was demonstrated that papilloma growth could be greatly reduced by giving animals supplemental arginine in the presence of small amounts of the arginase inhibitor, canavanine) provide evidence that suggests the following mechanism of action for the virus: viral DNA introduces into rabbit epithelium the information for the synthesis of an arginase for which the cells have no control mechanism. The arginase depletes cellular arginine and, in turn, the synthesis of arginine-rich nuclear histones (2), thereby freeing the nucleus for greater synthetic activity (4, 35), which results in more rapid growth of the papilloma cells. Domestic rabbit papillomas induced with purified virus derived from wild rabbit papillomas were shown to contain an antigen which reacts immunologically like a wild rabbit antigen. It was distinct from the arginase, the protein coat of the virus, and the Vx-2 antigen. The presence of the wild rabbit antigen seems indicative of integration of the virus DNA in the host genome of the wild rabbit. Other incidental findings include the description of a simple method, accurate to within 1 per cent, for determining the partial specific volume of a protein, and the description of a modification of the Richards and Schachman method (9) enabling the determination of the molecular weight and homogeneity of a protein with as little as 0.25 mg and with an accuracy of 2 per cent.


1952 ◽  
Vol 96 (2) ◽  
pp. 159-174 ◽  
Author(s):  
Peyton Rous ◽  
John G. Kidd ◽  
William E. Smith

Tests were made to learn whether an anaplastic, epidermal carcinoma, the Vx2, which had originated more than 8 years previously from a virus papilloma in a domestic rabbit, still rendered its hosts immune to the virus. It had done so in the first 22 successive groups of animals to which it was transferred during a period of 3½ years, its growth regularly eliciting a blood antibody that neutralized the Shope virus and fixed complement in mixture with it; and on the assumption that this would continue to be the case no further observations were made for nearly 4½ years more. Then direct inoculation of animals carrying the tumor in its 46th Generation showed them to be as susceptible to the virus as normal rabbits; and sera procured from hosts of the 46th, 47th, 48th, and 50th Generations failed to neutralize the virus or fix complement with it. Tests of this last sort, repeated at intervals since,—most recently with sera from animals carrying the tumor in its 73rd Generation,—have yielded consistently negative findings. Loss of the power to immunize against the papilloma virus was not attended by any perceptible change in the Vx2 carcinoma. Manifestly the antigen responsible for the immunity cannot, as such, have been the actuating cause of the tumor. Attempts were made to infect the cells providing 48th Generation cancers, by mixing them with a suspension of the papilloma virus at time of implantation, or by injecting this agent into the blood stream of rabbits in which the tumog had already begun to proliferate. Its morphology and rate of growth remained unaltered; but tests of the animals to which transfers were next made yielded what appeared to be evidence of some slight immunity to the virus.


Virology ◽  
1960 ◽  
Vol 12 (1) ◽  
pp. 48-58 ◽  
Author(s):  
R.C Williams ◽  
S.J Kass ◽  
C.A Knight

1959 ◽  
Vol 109 (4) ◽  
pp. 423-428 ◽  
Author(s):  
Wilbur Fiske Noyes

A method has been devised to determine the location of infective Shope virus in the papillomas of cottontail rabbits. Frozen sections of the growths were burned selectively with a microcautery to destroy either the keratinized or proliferating layer and the sections were then applied directly to the sensitized epidermis of domestic rabbits. No papillomas appeared when the keratohyaline and keratinized areas had been eliminated leaving the proliferating cell layer, whereas papillomas arose when the proliferating cell areas were destroyed leaving the keratohyaline and keratinized layers. The results indicate that infective Shope papilloma virus is situated mainly, perhaps entirely, in the keratohyaline and keratinized areas of cottontail papillomas. This is in accord with the previous disclosure by the fluorescence technique that virus antigen in demonstrable quantity is present only in these situations.


Virology ◽  
1965 ◽  
Vol 27 (3) ◽  
pp. 273-281 ◽  
Author(s):  
S.J. Kass ◽  
C.A. Knight

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