Synovial sarcoma X breakpoint 2 peptide presented by MHC class I (SSX2/MHC class I)

Synovial sarcoma X breakpoint 2 (SSX2) is a member of the cancer-testis antigen (CTA) family, which is characterized by restricted expression in the testis and high expression in various malignancies such as synovial sarcoma and melanoma (UniProt Q16385). The SSX2-derived peptide, most commonly the KASEKIFYV sequence (SSX2 41-49), is processed and presented on the cell surface by MHC class I molecules, particularly HLA-A*02:01 (Ayyoub et al., 2002). This peptide-MHC complex serves as a specific target for immunotherapy because the testis, while expressing the protein, lacks the MHC class I molecules necessary for T-cell recognition, making the complex tumor-specific (Smith et al., 2011). Therapeutic strategies targeting this complex include T-cell receptor (TCR) engineered T-cell therapies, such as GSK3845097, and peptide-based vaccines designed to stimulate a cytotoxic T-lymphocyte response (ClinicalTrials.gov NCT04843917). By binding to this specific pMHC complex, these therapies aim to selectively eliminate cancer cells while sparing healthy somatic tissues. The development of these agents represents a significant effort in precision oncology to treat advanced solid tumors that express SSX2.

Other names

SSX2 peptide-HLA complexSSX2(41-49)/HLA-A*02:01Cancer-testis antigen SSX2 peptideSSX2-pMHC

Recognition of the SSX2 peptide-MHC complex by T-cell receptors (TCRs) on cytotoxic T-lymphocytes, triggering the release of perforins and granzymes to induce tumor cell apoptosis.