Human telomerase reverse transcriptase peptide–HLA class II complex (hTERT–HLA-II complex) (hTERT–HLA-II)

The human telomerase reverse transcriptase (hTERT) peptide–HLA class II complex is a specialized immunological target consisting of telomerase-derived peptide fragments bound to Human Leukocyte Antigen (HLA) class II molecules. hTERT is the catalytic subunit of telomerase, an enzyme essential for maintaining telomere length and cellular immortality, which is overexpressed in approximately 85–90% of all human cancers while remaining largely absent in most healthy somatic cells (Source: PubMed, PMID: 28923534). While HLA class I complexes typically present antigens to CD8+ cytotoxic T cells, the presentation of hTERT peptides via HLA class II molecules is critical for activating CD4+ T-helper cells. These helper cells play a central role in orchestrating a durable anti-tumor immune response by secreting cytokines that enhance the activity of cytotoxic effectors and help overcome the immunosuppressive tumor microenvironment (Source: Nature Reviews Cancer, 2021). Therapeutic strategies targeting these complexes, such as the UV1 vaccine, utilize long peptides to ensure broad HLA class II coverage across diverse patient populations. Because telomerase activity is vital for the continued proliferation of cancer cells, hTERT is considered a 'universal' tumor antigen with a significantly lower risk of immune escape through antigen loss compared to other targets (Source: Journal of Clinical Oncology, 2020).

Other names

hTERT peptide-MHC class II complexTelomerase peptide-HLA class II complexhTERT-derived peptide-HLA-II complexhTERT-HLA-DR complex

Induction of hTERT-specific CD4+ T-helper (Th1) cells that recognize hTERT peptides presented by HLA class II molecules on tumor cells or antigen-presenting cells, leading to the secretion of pro-inflammatory cytokines (IFN-gamma, TNF-alpha) and the recruitment/activation of cytotoxic CD8+ T cells.