Tumor Immunity in the Chick Embryo

Abstract

The biological study of transplantable tumors in animals has developed and established certain principles, some of which have later been found to have interesting variations; thus, it has been shown that a tumor from one species will not grow progressively in another species of animal. But there are exceptions to this general rule in the fact that the young of one species are susceptible, for a certain period during their development and growth, to tumors from another species. This has been shown to be true when rat and mouse tumors are inoculated into the chick embryo (Murphy (1), Stevenson (2)), and also when mouse tumors are inoculated into new-born rats (Bullock (3)). In a later communication Murphy reported that this period of susceptibility could be terminated in the chick embryo, by the introduction of a graft of adult chicken spleen. On this observation and the work of Da Fano (7) he based his ingenious hypothesis regarding the function of the lymphocyte in immunity to transplanted tumors. This hypothesis was weakened, however, by Bullock9s (3) discovery that new-born rats, ordinarily susceptible to inoculation with a mouse tumor, did not become refractory even when adult rat spleen and tumor were simultaneously inoculated. This is in exact contradiction to the findings of Murphy in the chick embryo; in each case the attempt is made to immunize against a tumor of a certain species growing upon a foreign soil, with tissues derived from this foreign soil. This interesting statement of Murphy9s, according to which the chick embryo presents an exception to the findings in another species of animal that has a similar brief period of susceptibility, seemed to indicate that a further investigation of the immune reaction of the chick embryo to tumors of the rat and mouse was necessary. With this in view, a short series of experiments was undertaken to discover whether or not tumors other than the Jensen rat sarcoma, which Murphy (4) used in his experiments, react in a similar manner.