Definition

A peptide cancer vaccine composed of a long peptide, containing amino acids 19 through 27 (FMTYWHLLNAFTVTVPKDL), obtained from the tumor-associated antigen (TAA) and immune checkpoint molecule programmed cell death-1 ligand 1 (PD-L1), with potential immunomodulating and antineoplastic activities. Upon vaccination with long PD-L1 peptide vaccine, the peptide may activate the immune system to induce an immune response against PD-L1-expressing cells. This may induce a cytotoxic T-lymphocytes (CTLs)-mediated immune response against PD-L1-expressing tumor cells. PD-L1 is overexpressed on many human cancer cell types as well as on antigen presenting cells (APCs) and immunosuppressive cells in the tumor micro-environment (TME), such as regulatory T cells (Tregs). PD-L1 binding to its cognate receptor programmed cell death protein 1 (PD-1; PDCD1; CD279) on T cells suppresses the immune system and results in increased immune evasion and decreased CTL activation.