Transient expansion of peptide-specific lymphocytes producing IFN-γ after vaccination with dendritic cells pulsed with MAGE peptides in patients with mage-A1/A3-positive tumors

Assessment of T-cell activation is pivotal for evaluation of cancerimmunotherapy. We initiated a clinical trial in patients with MAGE-A1and/or -A3 tumors using autologous DC pulsed with MAGE peptides aimedat analyzing T-cell-derived, IFN-γ secretion by cytokine flowcytometry and ELISPOT. We also tested whether further KLH additioncould influence this response favorably. Monocyte-derived DC weregenerated from leukapheresis products. They were pulsed with therelevant MAGE peptide(s) alone in group A (n=10 pts) andadditionally with KLH in group B (n=16 pts). A specific buttransient increase in the number of peripheral blood T lymphocytessecreting IFN-γ in response to the vaccine peptide(s) was observed in6/8 patients of group A and in 6/16 patients of group B. We concludethat anti-tumor vaccination using DC pulsed with MAGE peptides inducesa potent but transient anti-MAGE, IFN-γ secretion that is notinfluenced by the additional delivery of a nonspecific, T-cellhelp.