Persistent immunity after therapeutic vaccination targeting HER2/neu correlated with post-vaccination magnitude of interferon gamma Elispot responses

Methods Interferon gamma Elispot data was abstracted from patients enrolled in 3 clinical trials (n = 86) utilizing therapeutic vaccination targeting HER2/neu with long-term follow-up. A positive response/immunity was defined as a precursor frequency of greater than 1:20,000 or 50 interferon gamma corrected spots per well/10 peripheral blood mononuclear cells. Responses were evaluated at baseline study entry, at one month after completion of vaccinations and at long-term follow-up, the last time point available at week 24-36. Correlative statistical analysis was performed using Pearson product-moment correlation coefficients of least-squares regression.