Antibodies and Soluble Tumour-specific Antigens in Blood and Lymph of Rats with Chemically Induced Sarcomata

In confirmation of other studies it has been shown that antibody directed against the tumour specific transplantation-type antigens (TSTAs) cannot be detected in rats with a tumour growing intramuscularly but appears within a few days after excision of the tumour. Circulating antibody is found in the serum of rats with lymph node metastasis following excision of the primary. Absorption by the intramuscular tumour of circulating antibody does not account for the absence of antibody since the antibody levels in thoracic duct lymph in rats with tumours in the leg are also very low and rise rapidly after tumour excision. Antibody is released by the draining nodes directly into the lymph and must pass through the thoracic duct before entering the blood. Under these conditions low levels of antibody activity in lymph cannot be ascribed to absorption by the tumour. It is postulated that TSTA is released from the tumour into the lymph. Following injection of tumour cells into immunized rats the level of antibody falls and this is attributed to release of TSTA from the injected cells. The possible role of antigen release from tumours in determining the host reaction to the tumour is discussed.