Differential rate of age-related decline in immune functions in genetically defined mice with different tumor incidence and life span.

Immunological studies were performed in aging C57BL/6 and BDF1 mice. In C57BL/6 mice the incidence of malignant tumor was high and their mean life span was 665 days in males and 649 days in females. In BDF1 mice, the incidence of malignant tumors was significantly lower, and their mean life span was 954 days in males and 846 days in females. Immunologically, either the onset of decline occurred earlier, the rate of the age-related decline in activity was more rapid, and/or the magnitude of decline was greater in the shorter-lived C57BL/6 than in the longer-lived BDF1 mice. The close relationship between (a) the susceptibility especially to malignant lymphoma; (b) the onset, rate and magnitude of age-related decline in T-cell-dependent immunologic activities, and (c) the life span would suggest that T-cell immunity may be playing an important role in the resistance against life-shortening malignant lymphoma in C57BL/6 mice.