CpG oligodeoxinucleotides functions as an effective adjuvant in aged BALB/c mice.

During aging, there is an increased rise in susceptibility to infectious diseases. However, it is still unresolved whether standard vaccine adjuvants are efficient in the elderly. We report that immunization with OVA plus synthetic oligodeoxinucleotides containing immunostimulatory CpG motifs (CpG-ODN) stimulates specific Th1 response in aged mice. The immunization with OVA/CpG-ODN induced an increase in CD19+ cells. These cells from aged mice in vivo captured OVA-FITC as efficiently as those from young mice. Interestingly, naïve aged mice, which showed Th2 polarization and up-regulation of the expression of GATA-3, with immunization with OVA/CpG-ODN inducing Th1-specific response but maintaining a Th2 pattern in response to a non-specific stimulator of T cells. Our data suggest that the response elicited by CpG-ODN in aged mice have similar properties to the response developed in young mice, emphasizing the importance of the use of this adjuvant during aging.