INCIDENCE AND SPECIFICITY OF THE ANTIBODY FOR A DISTINCTIVE CONSTITUENT OF THE BROWN-PEARCE TUMOR

INDUCED ANTIBODIES THAT REACT IN VITRO WITH SEDIMENTABLE CONSTITUENTS OF NORMAL AND NEOPLASTIC TISSUE CELLS : PRESENCE OF THE ANTIBODIES IN THE BLOOD OF RABBITS CARRYING VARIOUS TRANSPLANTED CANCERS

Antibodies were found in the blood of certain rabbits carrying one or another of four transplanted cancers (Brown-Pearce and V2 carcinomas; RSI and Kato sarcomas) which will fix complement in vitro in mixture with saline extracts of various normal and neoplastic rabbit tissues—including liver, kidney, spleen, and the four tumors mentioned—and chick embryo tissue as well. These antibodies, which have been called induced tissue antibodies, are similar to the natural antibodies previously described (2) in that they react with those constituents of the various tissue cells that prove readily sedimentable in the high speed centrifuge; they differ from the natural antibodies in being absent from the blood of normal rabbits and in withstanding 65° C. for 30 minutes. Certain quantitative differences suggest that the induced tissue antibodies have somewhat various affinities, depending in part upon the type of neoplasm carried by the host. They may perhaps be consequent on antigenic differences between the sedimentable constituents of the tumor cells and those of the new hosts; for they were not found in the blood of rabbits carrying papillomas and cancers composed of the animals' own cells, and not in that of rabbits in which multiple vaccinia or fibroma virus lesions had recently regressed. The characters of the sedimentable constituents of normal and neoplastic tissue cells, as revealed thus far by chemical, morphological, and serological studies, have recently been discussed (2,8). In this relation, it has seemed essential to recognize the induced antibodies here described, particularly since they may complicate serological studies aimed at disclosing distinctive sedimentable substances in tissue cells. In an associated paper experiments are reported which bear upon the relation between the induced tissue antibodies and an antibody that reacts specifically with a distinctive sedimentable constituent of Brown-Pearce carcinoma cells (7).

Structural changes produced in Brown-Pearce carcinoma cells by means of a specific antibody and complement

Structural changes were regularly observed in Brown-Pearce rabbit carcinoma cells that had been brought into contact, in the presence of complement, with rabbit serum containing an antibody that reacts specifically with a distinctive sedimentable constituent of the carcinoma cells. The cellular changes appeared rapidly and were accompanied by an equally rapid loss of viability. The structural changes, as disclosed by histological and cytological methods, including phase contrast microscopy, were described in detail and illustrated. Essentially they were characterized by the entrance of considerable quantities of fluid into the cell, together with swelling and disorganization of its cytoplasm, vesiculation and rupture of the bulk of its cytoplasmic particles, and rapid and virtually complete loss of cytoplasmic basophilism. The plasma membranes, though stretched thin about the swollen cytoplasm of the altered cells, and otherwise changed also, remained unruptured during many hours' observation. The nuclei of the altered cells, however, remained relatively un-changed, their membranes persisting unruptured and their sap remaining wholly transparent and undiminished in amount for long periods, while within it the chromatin retained its staining properties, though sometimes becoming clumped and marginated; by contrast, the nucleoli of the treated cells promptly shrank and lost much of their affinity for the basic dyes. The experimental conditions under which the structural changes became manifest were given in detail, together with an analysis of the findings and brief mention of certain of their implications for cytology and immunology.

SUPPRESSION OF GROWTH OF BROWN-PEARCE TUMOR CELLS BY A SPECIFIC ANTIBODY : WITH A CONSIDERATION OF THE NATURE OF THE REACTING CELL CONSTITUENT

Experiments are reported in detail which show that an antibody which appears in the blood of certain rabbits implanted with the Brown-Pearce tumor or injected with cell-free extracts of it is capable of suppressing the growth of the tumor cells under a variety of experimental conditions, the effects of the antibody being wholly distinct from those of unknown factors that frequently bring about regression of the growth. The implications of the findings are discussed with particular reference to facts indicating that the distinctive cell constituent with which the antibody reacts may play a significant part in the proliferative activities of the Brown-Pearce tumor cell.