PyNTTTTGT prototype oligonucleotide IMT504, a novel effective adjuvant of the FMDV DNA vaccine.

Synthetic oligodeoxynucleotides (ODNs) such as CpG can stimulate B and plasmacytoid dendritic cells in vertebrate immune systems. Several studies showed that non-CpG ODNs could also induce strong stimulation of B and T cells. PyNTTTTGT ODNs, non-CpG ODNs, can activate and cause immunoglobulin secretion by B cells and proliferation of T cells in vivo. By using PyNTTTTGT ODNs as an adjuvant for a FMDV DNA vaccine, we found that levels of antibody production, T-cell proliferation, and CTL activity were significantly increased compared with the DNA vaccine alone. Compared with the adjuvant effects of CpG ODNs on DNA vaccination, similar levels of antibody production and T-cell proliferation, and higher levels of CTL activity and IFN-gamma expression in CD8 T cells were induced by the IMT504 ODNs. On the other hand, RT-PCR results show that IMT504 ODN may activate the DNA sensor of DAI (DNA-dependent activator of IFN regulatory factors) and partially stimulate TLR9. At this point, the PyNTTTTGT prototype IMT504 ODN can reasonably be predicted to be a good adjuvant for FMDV DNA vaccine in small animals, but its efficacy in larger animals remains to be explored.