Gene Gun Vaccination
Four of six mice that received a single Helios gene gun vaccination developed an antibody response to the HBsAg (detected at a 1:10 antiserum dilution), with one of these responses measured at a dilution of 1:100. All six mice that received two gene gun vaccinations demonstrated antibody responses, detectable at an antiserum dilution of 1:10,000 for two mice, 1:1,000 dilution for three mice, and 1:100 dilution for one mouse, respectively (Figure 2).
Antibody Response by Subclass
The relative binding activity of the anti-IgG1 antibody was greater than that of the anti-IgG2a antibody. After taking this into account, we found that intramuscular vaccination with pCMV-S resulted in a predominantly IgG2a response, while Helios gene gun vaccination resulted in a predominantly IgG1 response (Figure 3).
Duration of Antibody Response Antisera obtained at weeks 4, 6, 9, and 12 after gene gun vaccination were all assessed by ELISA for the presence of antibodies to HBsAg. At all time points there was a significantly higher antibody titer compared to unimmunized control sera at a dilution of 1:1,000 (Figure 4). Antibody titers for the week 12 antisera are shown in Figure 5.
Delivery of the pCMV-S p