Age-dependent tolerance to an endogenous tumor-associated antigen.
Immunologic tolerance to endogenous antigens reduces antitumor responses. Gp70 is an endogenous tumor-associated antigen (TAA) of the BALB/c-derived colon carcinoma CT26. We found that expression of gp70 mRNA is detectable in tissues of mice 8 months of age and older. We showed that expression of gp70 establishes immunologic tolerance and affects antitumor immunity in a similarly age-dependent manner using gp70-deficient mice. We found that tumors grew in all gp70-sufficient mice, while approximately half of gp70-deficient mice controlled tumor growth with endogenous T-cell responses. Protection in gp70-deficient mice correlated with more robust gp70-specific CTL responses, and increased numbers and avidity of responding antigen-specific T cells after vaccination. We conclude that immunosurveillance may decline with age due to increased or de novo peripheral expression of endogenous TAAs.
Pubmed ID: 18329760 RIS Download
Aging | Animals | Antigens, Neoplasm | Colonic Neoplasms | Female | Immune Tolerance | Male | Mice | Mice, Inbred BALB C | Mice, Inbred C57BL | Mice, Knockout | T-Lymphocytes