PSMB9 and nasopharyngeal carcinoma: From the CD8high cell population, LMP1 (YLQ) and LMP2 (LLW, GLG) antigen-specific CD8+ T cells and CD8+Foxp3+ Tregs (Tcregs) were isolated from PBMCs and TILs of NPC patients (Figure 5A); however, only antigen-specific CD8+ T cells but not CD8+Foxp3+ Tregs (Tcregs) were observed in PBMCs of HLA-A2 positive healthy donors (Additional file 2).