Our data from DCs and LCs sensitized with different antigens have demonstrated that (1) BMDCs from older mice can be sensitized with a specific antigen to facilitate normal presentation function; peptide-sensitized DCs can be a very potent and effective therapeutic vaccine in age-related diseases when treated with the proper antigen, (2) mutant Aβ peptide can stimulate CD8α+ DCs at a much higher level; this novel function may boost immune activity and help AD patients to withstand progressing AD symptoms. The gene discussed is CD8A; the disease is Alzheimer disease.