Immunostimulatory effects of plasmid DNA and synthetic oligodeoxynucleotides

Abstract

Nucleic acid immunization is a new vaccination technology. DNA vaccines do not only carry the genetic information for the antigen of interest but also deliver an adjuvant effect due to the presence of immunostimulatory sequences within the plasmid backbone. It is generally assumed that the adjuvant properties of plasmid DNA are equal to those described for oligodeoxynucleotides (ODN) containing immunostimulatory CpG motifs. To challenge this hypothesis we have carried out a series of experiments comparing the ability of single-and double-stranded ODN containing CpG motifs to induce the activation of mouse spleen cells. Moreover, we compared the immunostimulatory properties of plasmids that were modified by the addition of two to four CpG motifs. Our results establish that plasmid DNA express their adjuvanticity as either double or single strands, and no differences were observed between modified and unmodified plasmids. On the other hand, the strongest stimulatory ODN sequences lost their adjuvant properties when administered as double-strand DNA. Furthermore, the profile of cytokines induced on spleen cells by plasmid DNA and ODN is different. Strikingly, plasmid DNA induces a moderate synthesis of IL-6 and a strong synthesis of IFN-+ , whereas stimulation with ODN showed an inverse profile with a higher increase in the synthesis of IL-6 but a moderate increase in IFN-+ . Finally, in vivo studies were consistent with the results obtained in vitro. Mice immunized with modified or unmodified plasmids encoding the glycoprotein D of HSV showed similar levels of cellular and humoral immune responses.

Th1 polarized response induced by intramuscular DNA-HSP65 immunization is preserved in experimental atherosclerosis

“…Different cellular sources may contribute to this synthesis, mainly macrophages and Th2 cells which have been described as the main source of this cytokine. This increase is consistent with the high level of specific antibody production observed by both immunization routes and also with the description of high IL-6 levels in animals injected with other genetic vaccines (31,32). Interestingly, a contribution of this cytokine to atherogenesis in both human and experimental models has been described.…”

TLR9 Agonists Oppositely Modulate DNA Repair Genes in Tumor versus Immune Cells and Enhance Chemotherapy Effects

“…with CpG-ODN (26). Spleen cells were chosen for this analysis on the basis of previous studies establishing that the spleen accurately reflects the breadth of immunity induced by CpG-ODN in vivo (27)(28)(29)(30)(31)(32). Expression levels of mRNA in mouse spleen cells were monitored by microarray at different times after in vivo CpG-ODN treatment.…”

Tuberculosis vaccine development :The development of a novel (preclinical) DNA vaccine

“…[48][49][50] These vaccines are also able to activate innate immune responses. They interact with Toll-like receptor 9 (TLR 9: the pattern recognition receptor) through unmethylated CpG oligodeoxynucleotides (CpG ODNs9), 51,52 resulting in the upregulation of cytokines gene expression through MyD88 molecule. [53][54][55][56] DNA vaccines have been in general proved to be safe and well tolerated in preclinical and clinical studies.…”