Immunization with DNA vaccines in early life: Advantages and limitations as compared to conventional vaccines

Conclusion: DNA vaccines favorably compare to conventional vaccines in their unique capacity to induce, in murine models, adult-like antibody, Th1 and CTL responses at a time of yet significant immune immaturity. Immune responses to DNA vaccines are, however, significantly slower than the one induced by adjuvanted subunit or live vaccines. Although they persist for life in mice, preliminary data in non-human adult primates suggest that this could not be the case in higher mammals. The issue of potential tolerance induction will likely not emerge as a critical feature of human neonatal DNA immunization. However, DNA vaccines are unlikely to prove superior to conventional vaccines in their capacity to circumvent the inhibitory influence of maternal antibodies. Thus, the greater perspectives for neonatal DNA immunization could be found in models where the induction of Th1 and CTL responses are of utmost importance. These are essentially infections with intracellular agents responsible for severe/persistent infections upon early exposure and for which no current efficient and safe conventional vaccine exists. Evaluating neonatal DNA immunization strategies against RSV or herpes viruses, tuberculosis or Chlamydiae therefore emerge as sound prioritie