Neoantigen–Human Leukocyte Antigen class II complex (Neoantigen–HLA-II)

Neoantigen–Human Leukocyte Antigen (HLA) class II complexes are molecular assemblies consisting of a tumor-specific mutant peptide (neoantigen) non-covalently bound to an HLA class II molecule, such as HLA-DR, HLA-DQ, or HLA-DP. These complexes are primarily presented on the surface of professional antigen-presenting cells (APCs) or, in some cases, tumor cells themselves, where they serve as the primary ligand for CD4+ T-cell receptors (Alspach et al., Nature 2019). Unlike HLA class I complexes that interact with CD8+ T cells, HLA class II-mediated recognition is crucial for providing help to the immune system, ensuring a sustained and memory-forming anti-tumor response (Sahin et al., Nature 2017). Because neoantigens are derived from somatic mutations unique to the patient's tumor, these complexes represent highly specific targets that minimize the risk of central tolerance and autoimmunity (Ott et al., Nature 2017). Current therapeutic approaches include personalized cancer vaccines and TCR-engineered T-cell therapies designed to exploit these complexes to induce potent, individualized immune attacks against malignancies (Tran et al., NEJM 2014).

Other names

Neoepitope–MHC class II complexTumor-specific antigen–HLA-II complexMutant peptide–HLA class II complexTSA–HLA-II complex

Binding of the neoantigen-HLA-II complex to the T-cell receptor (TCR) of CD4+ T cells, leading to T-cell activation, proliferation, and the release of pro-inflammatory cytokines that enhance the anti-tumor activity of the immune system (Alspach et al., Nature 2019).