Processing of tumor antigen differentially impacts the development of helper and effector CD4+ T-cell responses

Abstract

CD4+ T cells contribute to the antitumor T-cell response as both effectors that promote tumor rejection and helpers that facilitate the activation of other antitumor effector cells, such as CD8+ T cells. Maximal engagement of both effector and helper CD4+ T-cell responses is a desirable attribute of cancer vaccines. We have employed the B16F10 murine melanoma model and a series of recombinant adenovirus (Ad) vaccines expressing mutant forms of the tumor antigen, dopachrome tautomerase, to investigate the relationship between antigen processing and the antitumor CD4+ T-cell response. Our results have revealed an unexpected dichotomy in the generation of helper and effector CD4+ T-cell responses where CD4+ T effector responses are dependent upon protein processing and trafficking, whereas CD4+ T helper responses are not. The results have important implications for strategies aimed at augmenting antigen immunogenicity by altering intracellular processing and localization. © The American Society of Gene & Cell Therapy.