Nucleic acid immunizations.

This unit provides protocols for two broadly used methods of DNA immunization: saline injections and gene gun deliveries of DNA. Saline injections deliver DNA into extracellular spaces; gene gun deliveries bombard DNA directly into cells. Support protocols present methods for preparation of DNA-coated gold beads, creation of cartridges containing these beads, and optimization of gene gun parameters.

Th1 genetic adjuvants modulate immune responses in neonates.

In these studies, we address the ability of DNA encoding Th1 cytokines to bias the isotype of antibody raised by neonatal or adult immunization with an influenza hemagglutinin expressing DNA (HA-DNA). Neonatal mice coimmunized with HA-DNA and either IL-12 or IFN-gamma-expressing DNA developed IgG2a-biased immune responses, regardless of inoculation method. In contrast, the Th1 genetic adjuvants had no effect on IgG subtype patterns in adults.

DNA vaccines for influenza virus: differential effects of maternal antibody on immune responses to hemagglutinin and nucleoprotein.

Maternal antibody is the major form of protection from disease in early life when the neonatal immune system is still immature; however, the presence of maternal antibody also interferes with active immunization, placing infants at risk for severe bacterial and viral infection. We tested the ability of intramuscular and gene gun immunization with DNA expressing influenza virus hemagglutinin (HA) and nucleoprotein (NP) to raise protective humoral and cellular responses in the presence or absence of maternal antibody. Neonatal mice born to influenza virus-immune mothers raised full antibody responses to NP but failed to generate antibody responses to HA.

Studies on antibody responses following neonatal immunization with influenza hemagglutinin DNA or protein.

Neonatal mice have immature immune systems with defects in several components of inflammatory, innate, and specific immune responses and develop a preferential T helper type 2 response following immunization with many vaccine antigens. These studies were undertaken to determine whether 1-day-old neonatal mice immunized with plasmid DNA expressing influenza A/PR/8/34 hemagglutinin (H1) by either intramuscular (im) or gene gun (gg) inoculation were capable of generating humoral responses comparable to those in mice immunized as adults. The newborn mice developed stable, long-lived, protective anti-H1-specific IgG responses similar in titer to those of adult DNA-immunized mice.