Adenosine deaminase activity in lymphocyte subpopulations of B-16 melanoma and normal C57BL bearing mice.

The activity of adenosine deaminase (ADA) was measured in thymus and spleen subpopulations separated by peanut agglutinin (PNA) of melanoma B-16 C57BL bearing mice and normal age-matched C57BL mice. Groups of 10 mice were used each time and the experiments were repeated 6 times. The adenosine deaminase activity in the PNA+ thymocytes of B-16 bearing mice was about 2.5 times lower than that of the normal C57BL mice while the ADA activity in the PNA+ fraction of spleen of the B-16 melanoma bearing mice was 2.5 times higher. These results demonstrate that the tumor burden probably induces a different redistribution and traffic of lymphocytes from one lymphopoietic organ to another. This traffic can also explain the thymus involution and spleen enlargement found in the B-16 mice.