Figure 1.

DNA vaccine delivery with electroporation (EP) increases cellular and humoral responses. A DNA vaccine encoding human prostate–specific antigen (PSA) was administered by intramuscular injection (IM) or by IM plus EP (IM+EP). Animals received 2 vaccinations spaced 2 weeks apart. Cellular and humoral responses were determined 1 week after the second immunization. PSA-specific T-cell responses were determined by interferon (IFN) gamma enzyme-linked immunospot (A) and PSA-specific seroconversion by enzyme-linked immunosorbent assay (B). n = 5 per group. OD, optical density; SFC, antigen-specific spot forming cells per 106.