The tumor antigen p53 is mutated frequently and overexpressed in colorectal cancer. As a result, patients with this type of cancer commonly display p53-specific T-helper (Th) immunity. Examination of the cytokines produced by these Th-cells showed that a majority of the proliferative p53-specific T cell cultures produced none of the key cytokines (IFNgamma, TNFalpha, IL-4, IL-5 or IL-10), indicating that these p53-specific Th-responses are not polarized. In patients who exhibited p53-specific reactivity against multiple p53-epitopes, non-polarized responses could be found side by side with polarized Th-responses that produced INFgamma or other cytokines such as IL-10. Patients who exhibited p53-specific IFNgamma-producing Th cell-immunity before surgical excision of the tumor displayed higher numbers of tumor infiltrating intraepithelial leukocytes (p = 0.04) than patients lacking such responses, suggesting that the systemic presence of p53-specific Th-cells positively affects local tumor-immunity. Our data concerning the polarization-state of p53-specific Th immunity in colorectal cancer patients support the use of vaccine formulations that induce strong Th1-polarized p53-specific immunity to ensure proper (re-)programming of the anti-tumor response.
Copyright 2003 Wiley-Liss, Inc.