The injection of extracts of leukemic and Hodgkin’s disease tissues of man elicit an antibody reaction in both man and rabbit. This response is similar to that elicited by leukemic mouse tissues when injected into rabbits. The antibody reaction may be demonstrated by the technics of passive cutaneous anaphylaxis, immunodiffusion, microprecipitin and immunofluorescence. Tissue extracts from non-leukemic individuals do not elicit a similar response. Rabbits immune-tolerant to normal human tissues produce antibodies specific to leukemic human antigens. Antibodies develop in those individuals who are exposed for a long time to either human or mouse leukemia.
These immunologic studies demonstrate specific antigenic differences between normal and leukemic tissue extracts. It is postulated that the difference between normal and leukemic extracts is the consequence of the presence of viruses or the alterations caused by them.