CAP1-6D

CAP1-6D (Carcinoembryonic antigen peptide 16d) is a cytotoxic T lymphocyte (CTL) agonist peptide that enhances the immunogenicity of the CAP1 peptide and promotes T cell responses.

Method: CEA-specific CTL lines (T-N2, T-Vac8, T-15) were established from PBMC of HLA-A2-positive healthy donors and patients immunized with a CEA vaccine. CTLs (1×10⁵ cells/well) were co-cultured for 24-48 hours with T2 cells or autologous EBV-B cells (1×10⁵ cells/well) pulsed with 0.00002–20 μg/mL CAP1-6D. The levels of cytokines (GM-CSF, IFN-γ, TNFα, IL-4, IL-10) in the culture supernatant were measured by ELISA.
Result: CAP1-6D stimulated CEA-specific CTLs to produce GM-CSF, IFN-γ, and TNFα. At low concentrations of 0.02–0.2 μg/mL, CAP1-6D induced high levels of cytokine production: GM-CSF reached 5,000–9,000 pg/mL, IFN-γ reached 4,000–8,000 pg/mL, and TNFα was detectable at 0.2 μg/mL. CAP1-6D induced little to no production of IL-4 and IL-10 (both <3 pg/mL), and the cytokine profile induced was of the Tc1 type [1].