K562/HLA-E cells pre-incubation with peptides
Before incubation with peptides, K562/HLA-E*0103 cells were incubated at 26℃ for 24 hours to adapt to the condition for antigen presentation in advance. K562 cells were then incubated with peptides constructed (ul/10 cells) at 26℃ for 19h for the next assay.
Ex Vivo IFN-γ enzyme-linked immunospot assay (ELISPOT)
The human IFN-γ ELISPOT kit (DAKEWE Biotech Company, China) was used to detect the capacity of IFN-γ production by CD8+ T cells stimulated with specific antigenic peptides presented by K562/HLA-E cells as previously. The spots representing peptide-specific IFN-γ-producing CD8+ T cells were counted using an automatic ELISPOT reader (Cellular Technology Limited, USA). Adjusted spot-forming cells (SFCs) after subtracting negative values are expressed as SFCs/106 cells.