Conventional influenza viral vaccines show poor efficacy in infants and young children due to the immaturity of the immune system, as well as the inherent limited immunogenicity and inability to stimulate cell-mediated immunity of the inactivated virus. In addition, they are limited by a poor side effect profile in this patient subgroup. Recently, they have shown that immunization of neonatal mice with plasmid DNA carrying hemagglutinin (HA) or nucleoprotein (NP) of the A/PR/8/34 influenza virus, as well as a chimeric pVH-TBplasmid carrying a major B cell epitope (HA 150-159) and the immunodominant CD4 T cell epitope (HA 110-120) of A/PR/8/34 influenza virus can confer some protection. The major aim of this proposal is to evaluate whether the partial protection against influenza virus they have observed previously in neonates can be enhanced. Specifically, they propose to construct a plasmid (pVH-CTB), which carries a chimeric VH gene with the immunodominant epitopes from influenza virus that are recognized by B (HA 150-159), CD4 T (HA 110-120), and CD8 T (NP 147-155) cells. In the first phase of the study, the pVH- CTB plasmid will be compared with our original plasmid cocktail of plasmid expressing influenza viral HA and NP genes and with UV-inactivated virus for its ability to confer protection against lethal challenge with influenza virus in neonatal mice. PROPOSED COMMERCIAL APPLICATION: The studies proposed in our grant application phase I and II are aimed at evaluating the effect of genetic immunization against influenza virus in newborns and infants. The rational for these studies follows epidemiological data in the field indicating that newborns and infants do not respond upon vaccination with formalin-inactivated virus, the current vaccine. We recently showed that DNA immunization with plasmids expressing influenza virus hemagglutinin (HA) or nucleoprotein (NP) genes prime neonates for a vigorous response against influenza virus. In phase I we studied the effect of DNA immunization on newborn mice and we showed that co-immunization with plasmids expressing HA, which induces B cell response, and NP, which induces CTL response, protected 100% of mice against challenge with live virus. Our preliminary data carried out in neonatal baboons showed that they developed a good anti-HA response after vaccination with HA gene. In phase II we would like to complete the experiments in neonatal baboons as well as to determine the safety of these plasmids. The results derived from these studies will represent the basis to apply to FDA for the initiation of a clinical trial in infants. We have applied for a patent for DNA immunization of newborns against influenza virus, which is under consideration by the US Patent Office. Alliance Pharmaceutical Corporation has a long experience of human trials with various products.
