Tumor-specific idiotype peptide–MHC complex (Id-pMHC)

Tumor-specific idiotype peptide–MHC complexes (Id-pMHC) are unique neoantigens found on the surface of malignant B-cells, such as those in follicular lymphoma and multiple myeloma (Bogen, 1996, Eur J Immunol). These complexes are formed when the unique variable regions (idiotypes) of the clonal B-cell receptor are processed into peptides and presented by Major Histocompatibility Complex (MHC) molecules (Kwak et al., 1992, NEJM). Because the idiotype sequence is a result of somatic hypermutation and V(D)J recombination unique to the tumor clone, the resulting Id-pMHC complex is a highly specific tumor-specific antigen (TSA) not found on healthy cells (Levy et al., 2011, Blood). T-cell receptors (TCRs) on CD4+ or CD8+ T-cells can recognize these complexes, triggering an immune response against the cancer (Schuster et al., 2011, JCO). Therapeutic approaches targeting Id-pMHC include personalized idiotype vaccines, such as Dasiprotimut-T, and the development of TCR-engineered T-cells designed to bind the complex with high affinity (Bendandi et al., 1999, Nat Med). However, clinical success has been limited by factors such as low antigen density on the cell surface and tumor-mediated immune evasion through MHC downregulation (Hock et al., 2002, Cancer Res).

Other names

Idiotype-derived peptide-MHC complexB-cell receptor idiotype-MHC complexIg-idiotype peptide-MHCTumor-specific idiotype-MHC

Activation of tumor-specific T-cells through TCR recognition of the idiotype peptide-MHC complex, leading to targeted lysis of malignant B-cells.