Effects of electroporation and targeting molecules on the cellular immune response.

<p>Immunizations of BALB/c mice (25 µg DNA in 50 µl NaCl per quadriceps) were performed without (−EP) or with electroporation (+EP). (A) Electroporation increased the amount of luciferase at the injection site. DNA encoding luciferase was delivered intramuscularly in the quadriceps without (−EP) or with electroporation (+EP), and the expression of luciferase was measured by <i>in vivo</i> imaging and bioluminescence (p/s: photons/second) at different time points after injection. The amount of luciferase differed significantly between the two groups from day 4, *p≤0.02, n = 3–4 muscles/group. (B, C) Cellular immune responses induced by the vaccibodies delivered by intramuscular DNA-injection without (−EP) or with electroporation (+EP). Splenocytes were harvested four weeks after immunization and incubated together with the MHC class I, P18-peptide (B) or a pool of overlapping peptides from gp120 (C) in IFNγ-ELISpot assay. n = 8 mice per group for CCL3-gp120 and n = 4 mice per group for αMHCII-gp120 and αNIP-gp120. In A–C: mean values and SEM are presented. B and C, for the groups of control mice (NaCl delivered with or without EP, and re-stimulated with P18 or gp120 peptides) the mean number of IFNγ-SFC/10⁶ splenocytes varied from 37 to 47 and is substracted from the number of spots in the respective samples from vaccibody-immunized mice.