SLLMWITQC

Peptide SLLMWITQC is a nonapeptide corresponding to residues 157–165 of the NY-ESO-1 antigen. It is derived from the cancer/testis antigen NY-ESO-1 (New York esophageal squamous cell carcinoma 1), a protein highly expressed in various tumor types (melanoma, neuroblastoma, etc.), while largely absent in normal tissue. Recognized only when presented on HLA-A*02:01 (MHC Class I), making it a key antigenic epitope for CD8⁺ T-cell immune recognition.

SLLMWITQC is an HLA-A2-restricted CD8⁺ T-cell epitope derived from NY-ESO-1, making it instrumental in eliciting T-cell responses against tumor cells. The 3D conformation of this peptide bound to HLA-A2 has been elucidated (PDB entry 1S9W), providing a structural basis for TCR interactions and stability in immunogenic assays. The epitope has been widely used in TCR-T cell therapies (e.g., 1G4 TCR) and vaccine development, with multiple clinical trials demonstrating efficacy—particularly in melanoma and synovial sarcoma.

Features & Benefits:

• T-Cell Activation Assays:
  Used to stimulate NY-ESO-1-specific CD8⁺ T cells in ELISPOT, intracellular cytokine staining (ICS), cytotoxicity, and proliferation assays with PBMCs or splenocytes.
• Vaccine Platforms:
  Incorporated into nanoparticle-based delivery systems to boost antigen-specific CD8⁺ T-cell responses, especially when co-delivered with adjuvants like CpG, enhancing IFN-γ secretion and cytotoxicity.
• Structural & Biochemical Studies:
  Enables understanding of MHC–peptide–TCR binding interactions, informing design of immunogenic analogs (e.g., substitution of terminal cysteine to improve stability).
• Immune Monitoring & Diagnostic Tools:
  Employed in tetramer staining or MHC-multimer assays to detect and quantify NY-ESO-1-specific T cells, aiding in monitoring immune responses during immunotherapy trials.
• Antibody & TCR-like Reagents:
  Used as the target epitope for development of TCR-like monoclonal antibodies (e.g., 3M4E5) that recognize peptide–MHC complexes, offering tools for detection or therapeutic targeting of tumor cells.

The SLLMWITQC peptide stands as a benchmark NY-ESO-1 epitope for immunological and therapeutic applications. Its strong immunogenicity, structural characterization, and practical utility make it indispensable for research in cancer immunotherapy, vaccine development, and T-cell diagnostics.

SLLMWITQC is a 9-residue synthetic peptide with the sequence Ser-Leu-Leu-Met-Trp-Ile-Thr-Gln-Cys. The sequence contains 1 cysteine residue, providing potential thiol/disulfide chemistry when the thiol is available; has a relatively high hydrophobic-residue fraction that can influence aqueous solubility and surface adsorption. These sequence-derived properties describe the reagent chemically; no specific receptor, enzyme, pathway, disease association, or biological activity is assigned without product-specific experimental evidence.

• thiol-selective conjugation or immobilization studies
• LC-MS/HPLC analytical method development
• sequence-specific assay controls

Sequence-derived chemical properties support reagent selection and experimental planning but do not establish biological function. Solubility, aggregation, adsorption, conjugation efficiency, and assay performance should be validated under the intended experimental conditions.