Immunochemical differences in deoxyribonucleoproteins from ormal and malignant canine tissues.

Deoxyribonucleic acid-protein (DNA-P) fractions were isolated from normal and malignant tissues of five tumour-bearing dogs and used as immunogens in ten albino rabbits. The immune sera were examined immunochemically using the techniques of passive haemagglutination, immunodiffusion, disc electrophoresis, disc immunoelectrophoresis, amino acid analysis and fluorescence quenching. Both types of DNA-P from each canine contained a common as well as a distinct antigenicity. After absorption of each serum with heterologous DNA-P, no cross reactions were observed between normal and malignant DNA-P. Although no definitive differences in amino acid composition existed between the proteins isolated from normal and malignant DNA-P of each dog, in two of the five tumour systems examined by disc electrophoresis a single band of protein was absent in the malignant proteins.