Pan HLA-DR-binding epitope (PADRE) (PADRE)

The Pan HLA-DR-binding epitope (PADRE) is a synthetic, non-natural 13-amino acid peptide designed to bind with high affinity to a broad range of human MHC class II molecules, specifically HLA-DR (Alexander et al., 1994). By binding to these pan-DR alleles, PADRE acts as a universal T-helper epitope, overcoming the genetic polymorphism of the HLA system that often limits the effectiveness of peptide vaccines in diverse populations (La Rosa et al., 2012). Its primary biological function is to stimulate CD4+ T-helper cells, which are essential for generating robust and sustained immune responses, including the activation of cytotoxic T lymphocytes and B cells (PubChem CID 16131100). In clinical applications, PADRE is frequently conjugated to or co-administered with disease-specific antigens to enhance the immunogenicity of vaccines targeting various cancers and infectious diseases (ClinicalTrials.gov). It has been incorporated into several investigational therapies, such as DPX-Survivac, to improve patient outcomes by ensuring a more potent and widespread immune recognition (IMV Inc.). The use of PADRE helps circumvent the need for patient-specific HLA matching in vaccine design, making it a versatile tool in modern immunotherapy.

Other names

PADREPan-DR-binding epitopeUniversal T-helper epitopeaKXVAAWTLKAAad-Ala-Lys-Cha-Val-Ala-Ala-Trp-Thr-Leu-Lys-Ala-Ala-d-Ala

PADRE binds with high affinity to a wide variety of HLA-DR molecules (MHC Class II) on antigen-presenting cells, thereby providing universal T-cell help by stimulating CD4+ T-helper cells to enhance the immune response against co-administered antigens (Alexander et al., 1994; PubChem CID 16131100).