Distinct Types of Antibodies in the Blood of Rabbits Carrying the Transplanted V2 Carcinoma

Abstract

Rabbits carrying the transplanted V2 carcinoma—a squamous-cell cancer derived originally from a virus-induced papilloma—regularly develop in their blood an antibody capable of neutralizing in vitro the papilloma virus (Shope) and capable also of fixing complement in mixture with it. 1 Further studies have now shown that the virus-neutralizing and complement-fixing titers of sera procured from rabbits carrying the V2 carcinoma invariably parallel one another, and that the antibody responsible for both reactions can be readily absorbed from the sera upon admixture with the virus. From the findings it appears certain that the antibody is directed against the papilloma virus per se, and that it is identical with the antiviral antibody present in the blood of rabbits carrying benign virus-induced papillomas, which is in turn identical with that present in the blood of rabbits injected with purified papilloma virus. 2 In further serum tests, carried out by the methods used in the serological study of the Brown-Pearce tumor, 3 we have recently encountered in the blood of rabbits with the transplanted V2 carcinoma two other types of antibodies, wholly distinct from one another and from the antiviral antibody just described.

When the sera of normal adult rabbits and of rabbits carrying the V2 carcinoma are heated at 56°C for 30 minutes and tested for capacity to fix complement in mixture with unheated 1:20 or 1:40 saline extracts of normal and neoplastic tissues (e. g., normal rabbit liver or kidney, V2 carcinoma, Brown-Pearce carcinoma) complement-fixation takes place in nearly all of the mixtures.∗ In general the normal sera react in dilutions as high as 1:16 to 1:32 with the normal tissue extracts, and only about half as well with the neoplastic-tissue antigens. On the other hand, sera from rabbits that have carried progressively enlarging V2 carcinomas for some weeks not only react with normal tissue extracts but are vastly more potent in mixture with the homologous antigen, generally fixing 2 units of complement completely in dilutions as high as 1:128 or 1:256 or more in mixture with extracts of the V2 carcinoma.