Figure 1.

Peripheral immune changes in response to tumor growth are observed in aged mice. Inguinal lymph nodes from female BALB/c mice either at 6-8 weeks old (young) or at 60-72 weeks old (aged) were sampled in the absence or presence of CT26 tumor cells subcutaneously implanted on the flank 15-17 days prior. (A) Immune cell subsets within inguinal lymph nodes of tumor-bearing mice compared to non-tumor bearing mice in both young and aged mice. 5-8 mice per group. (B) Comparison of the immune cell subsets within inguinal tumor-draining lymph nodes (TDLN) of young (left) and aged (right) mice bearing CT26 flank tumors. 18-19 mice per group. (C) Comparison of the immune cell subsets within inguinal lymph nodes of young (left) and aged (right) mice in the absence of a tumor. 9-11 mice per group. (D, E) Frequency of CD44^-CD62L^- effector (T_eff), CD44⁺CD62L^- effector memory (T_EM), CD44⁺CD62L⁺ central memory (T_CM) and CD44^-CD62L⁺ naïve cell subsets within the CD4⁺ T cell compartment in the inguinal lymph node (D) or TDLN (E) of both young and aged mice. The results include data from 2-3 experiments. *P < 0.05, **P < 0.01, ***P < 0.001 and ****P < 0.0001.