On Hemagglutination by Tumor Extracts.

Abstract

A report was made years ago on a distinct agglutinating action of extracts of tumors, of human and animal origin, on rabbit erythrocytes. 1 The question was raised whether the active substance might possibly be related to growth stimulating principles.

The agglutinating activity of the extracts disappears rather rapidly on standing and this property in itself differentiates the active substance from serum agglutinins, an inference probable also for other reasons. The agglutination phenomenon is shown also by Rous tumors.

Recently Mueller 2 described experiments which showed that the active principle of the Rous sarcoma deteriorates quickly on account of oxidation and that it can be preserved by the addition of cysteine and protection from the air. These results suggested similar experiments with the agglutinating extract of tumors. It was found that the deterioration of the agglutinating activity of tumor extracts (mouse sarcoma and Rous tumor) is also very markedly delayed when cysteine (1:500) is added to the solution and still more when the latter is covered with a layer of liquid paraffin. Thus the action is obviously different from agglutination by serum. A distinct agglutinating action, less intense than that of the tumors, was found in extracts of mouse embryos and mouse placenta.

Saline extracts of normal organs, as stated previously, did not show the agglutination phenomenon. Experiments are being made, using cysteine, in order to investigate whether a similar, though weaker, agglutinating action can be detected also in extracts of normal organs.