Superior induction of anti‐tumor CTL immunity by extended peptide vaccines involves prolonged, DC‐focused antigen presentation

MS Bijker, SJF van den Eeden… - European journal of …, 2008 - Wiley Online Library
MS Bijker, SJF van den Eeden, KL Franken, CJM Melief, SH van der Burg, R Offringa
European journal of immunology, 2008Wiley Online Library
Anti‐tumor vaccines consisting of extended CTL peptides in combination with CpG‐ODN
were shown to be superior to those comprising minimal CTL epitopes and CpG‐ODN, in that
they elicit stronger effector CTL responses with greater tumoricidal potential. We now
demonstrate that this improved performance is primarily due to the focusing of CTL epitope
presentation onto activated DC in the inflamed lymph nodes draining the vaccination site. In
the case of vaccination with minimal peptides, additional APC including T and B cells are …
Abstract
Anti‐tumor vaccines consisting of extended CTL peptides in combination with CpG‐ODN were shown to be superior to those comprising minimal CTL epitopes and CpG‐ODN, in that they elicit stronger effector CTL responses with greater tumoricidal potential. We now demonstrate that this improved performance is primarily due to the focusing of CTL epitope presentation onto activated DC in the inflamed lymph nodes draining the vaccination site. In the case of vaccination with minimal peptides, additional APC including T and B cells are also loaded with CTL epitopes. Our data suggest that circulation of these peptide‐loaded lymphocytes leads to epitope presentation in non‐inflamed lymphoid organs distal from the vaccination site, in the absence of potent costimulatory signals required for efficient CTL priming. The resulting blend of pro‐immunogenic and tolerogenic signals, which results in suboptimal activation of the CTL response, is avoided by vaccinating with extended CTL peptides. An additional advantage of extended CTL peptide vaccines is an increased duration of in vivo epitope presentation.
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