<p>(A) OVA-specific and (B) βGal-specific IgG in B6 mice (n = 5) gene gun-immunized with the fusion construct pCI-βGal-OVA or a mixture of pCI-OVA and pCI-βGal plasmids co-precipitated onto gold particles. For reference, groups of mice immunized with pCI-OVA (A) or pCI-βGal (B) were included. (C) OVA-specific IgG isotypes in B6 wild type mice or in mice constitutively expressing βGal (ROSA26), 2 weeks after 2 gene gun immunizations with pCI-OVA administered 2 weeks apart. (D) Serum IgG isotypes in B6 mice (n = 5) 2 weeks after two rounds of gene gun immunization, separated by a 2 week interval, with plasmid constructs in that secretion of OVA was prohibited by fusion to the C-terminus of, either, GFP, mCherry or βGal.</p
