Antigenic Properties of the Chicken Tumor

In the early investigations into the nature of the etiologic agent of fowl tumors, immunity phenomena were given some attention. The first observation was that the manifestations of resistance to these tumors in fowls, whether natural or acquired, are similar to those established for mammalian tumors, the principal feature being a local cellular reaction about the introduced graft (1). As was also established for mammals, the transfer of large m o u n t s of blood or serum from resistant animals had no influence on the growth of established tumors in susceptible ones. Later results indicated that two types of immunity exist, one directed against the etiologic agent as distinct from that directed against the malignant cell (2). That directed against the agent of each kind of tumor seemed to be the more specific (3). Rous, Robertson and Oliver (4) undertook to develop antibodies in other species by the injection principally of finely ground tumor tissue or of the blood of fowls in the last stages of the disease. Rabbits failed to show any neutralizing antibodies, but the sera of the injected geese did inactivate the agent and prevent the induction of tumors in chickens. Later Mottram (5) found evidence of antibodies in a few fowls in which tumors had retrogressed. MueUer (6), using cell suspensions of the chicken tumor, was able to induce antibodies in rabbits and ducks, while Gye and Purdy (7) working with tumor filtrates have reported on protective antibodies induced in ducks and goats. Andrewes (8) has found natural inhibitors for the tumor agents in the sera of two normal fowls and some evidence that such "antibodies" develop in the blood of chickens with a slow-growing fibroma which are effective against the agents of more malignant tumors.