Kinetics of tumor-specific T-cell response development after active immunization in patients with HER-2/neu overexpressing cancers

The ability of a cancer vaccine to elicit a specific measurable T-cell response is increasingly being used to prioritize immunization strategies for therapeutic development. Knowing the optimal time during a vaccine regimen to measure the development of tumor-specific immunity would greatly facilitate the assessment of T-cell responses. The purpose of this study was to overview the kinetics of HER-2/neu-specific T-cell immunity evolution during and after the administration of HER-2/neu peptide-based vaccination in the adjuvant setting. Furthermore, we questioned whether the presence of preexistent HER-2/neu T-cell immunity or the timing of immunity development over the course of active immunization influenced the intensity of the elicited HER-2/neu-specific T-cell immunity. Our findings demonstrate that maximal tumor-specific immune responses may occur toward the end of the vaccination regimen or even after the scheduled vaccines have been completed. Additionally, the presence of tumor antigen-specific immunity prior to vaccination is associated with greater magnitude immune responses.