Aging and cancerogenesis. IV. Interrelationships among age, immune response, and tumor incidence in several strains of mice.

Immune reactivity of mice with various incidences of spontaneous tumors was measured at different points in their lifespan. Cytotoxic activity of immune sera from 3- and 12-month-old mice was high or moderately high in AKR/J, SJL/J, and A/HeJ mice in which high incidences of spontaneous tumors occur by the 12th month, and in SWR/J and C3HeB/-FeJ mice in which high incidences of spontaneous tumors reportedly occur after 18 months of age. A decrease in primary antibody response accompanied old age in 4 of the 6 strains tested (including randombred Swiss ICR/Ha), but not in AKR/J or A/HeJ mice. These facts, together with previous tests of cellular response in these mice, imply that under these experimental conditions little correspondence exists between humoral and cellular response. Further, host immunity may be only secondarily implicated in neoplastic formation.