Tumor-associated antigen–derived peptides presented on Human Leukocyte Antigen class II (TAA-HLA-II)

Tumor-associated antigen (TAA)–derived peptides presented on Human Leukocyte Antigen (HLA) class II molecules are essential mediators of the adaptive immune response against cancer (NIH, 2021). While HLA class I molecules typically present endogenous peptides to CD8+ cytotoxic T cells, HLA class II molecules (HLA-DR, HLA-DQ, and HLA-DP) present peptides to CD4+ T helper cells (AACR, 2022). These peptides can be derived from exogenous proteins captured by professional antigen-presenting cells or from endogenous proteins via autophagy in tumor cells that aberrantly express HLA class II (NIH, 2012). Recognition of these complexes by CD4+ T cells triggers the secretion of pro-inflammatory cytokines like IFN-gamma and TNF-alpha, which orchestrate a robust anti-tumor environment and provide critical help for the expansion and memory of CD8+ T cells (BMJ, 2022). Therapeutic strategies targeting these complexes include multi-peptide vaccines like IMA950 and UV1, as well as engineered T-cell receptor (TCR) therapies designed to recognize specific peptide-HLA-II combinations (Neuro-Oncology, 2019). These treatments aim to enhance the immune system's ability to detect and destroy malignant cells by leveraging the helper and sometimes direct cytotoxic functions of CD4+ T cells. Challenges in targeting these molecules include the high polymorphism of HLA alleles and the potential for immune evasion through the downregulation of the HLA class II processing machinery (NIH, 2024). Despite these challenges, TAA-HLA-II complexes remain a high-priority target for developing personalized and universal cancer immunotherapies.

Other names

MHC class II-restricted tumor antigensTumor-associated antigen-MHC II complexesHLA-II tumor peptidesCancer-specific HLA-II-presented peptidesTumor-associated peptide-HLA class II complexes

Activation of CD4+ T helper cells through the recognition of specific peptide-HLA-II complexes, leading to the secretion of cytokines (e.g., IFN-gamma, TNF-alpha) and the orchestration of a coordinated anti-tumor immune response.