Synthetic Long Peptide processing & mechanism of action
The long peptide is taken up by the dendritic cell.
The long peptide enters the dendritic cell, where it is degraded into small pieces, containing epitopes recognized by T cells. The epitopes are a mix of T helper (Th) epitopes and cytotoxic T cell (CTL) epitopes. The T helper (Th) epitopes enter the MHC Class II presentation pathway via the endosomes. At the same time, the Cytoxic T Lymphocyte (CTL) epitopes enter the MHC class I presentation pathway, after proteasomal digestion.
T cell receptor binding to MHC-epitope complex, co-stimulation and T helper signals ensure optimal activation of the CTL (or CD8 killer T cell). This activation leads to expansion of the CTL.
Active CTLs will move to tumor cells that express the same epitopes via the MHC class I presentation.
The T cell receptor on the CTL recognizes MHC-peptide complexes on tumor cells and these activated T cells specifically kill the tumor cells, leaving normal cells intact.
In addition, active Th cells can also destroy tumor cells directly, or indirectly through activation of tumor-associated macrophages.
