CD4 and cancer: We found an increase in the number of CD4+ and CD8+T effector memory cells after priming with the immunogenic LDHC-derived peptides P11 (LDHC41−55) and P73 (LDHC288−303), and after co-culture with HLA-A*0201/LDHC positive breast cancer cells, suggesting that the CD8+ T effector memory cell population was responsible for the cancer cell killing in our in vitro model.