HBV antigen-specific humoral immune responses in pigs after three immunizations.

<p>Pigs were immunized with MIDGE-Th1 DNA vaccine candidates and Engerix-B on days 1, 29 and 57 (see legend <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0101715#pone-0101715-g004" target="_blank">Figure 4</a>) and serum samples were analyzed by ELISA for total S protein-specific antibodies (A), PreS1-specific IgG (B), S protein-specific IgG1 (C) and IgG2 (D) on day 71. Each symbol represents an individual pig serum sample. The mean is shown for each group as horizontal line (n = 3–5). For graphical and statistical purposes, samples without a titer were set to 10 in graph (B). Statistical analysis: (A) Dunnett, high S/Ctrl. *p = 0.011, Engerix-B/Ctrl. *p = 0.015; Tukey, Engerix-B/high L *p = 0.019, high S/high L *p = 0.012. (B) Dunnett, high L/Ctrl. ***p = 0.00002, Tukey, high L/low S ***p = 0.00002, high L/mid S ***p = 0.00007, high L/high S ***p = 0.00006, high L/Engerix-B ***p = 0.00004 (C) Dunnett, Engerix-B/Ctrl. ***p = 0.00002; Tukey, Engerix-B/low S **p = 0.002, Engerix-B/mid S ***p = 0.0002, Engerix-B/high S **p = 0.001. Engerix-B/high L ***p = 0.00003. (D) Dunnett, high S/Ctrl. **p = 0.006; Tukey, Engerix-B/high S *p = 0.024, high L/high S **p = 0.007, mid S/high S day 71: *p = 0.026. Other group comparisons were not significant.</p

Study design - immunization of pigs with MIDGE-Th1 DNA vaccine candidates and protein vaccine Engerix-B.

<p>Study design - immunization of pigs with MIDGE-Th1 DNA vaccine candidates and protein vaccine Engerix-B.</p

Duration of HBV antigen-specific humoral immune responses in individual animals.

<p>Pigs were immunized with MIDGE-Th1 DNA vaccine candidates and Engerix-B (see legend <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0101715#pone-0101715-g004" target="_blank">Figure 4</a>) and serum samples were collected and analyzed by ELISA for total S protein-specific antibodies (A), S protein-specific IgG1 (C) and IgG2 (C) on various test days up to 6 months after the third immunization. The animal number is shown in the legend of the graph.</p

Expression of HBV antigens in CHO-K1 cells.

<p>Cells were transfected with expression vectors encoding the S or the L protein or eGFP as control (Ctrl.). Expression in cell lysates was detected by Western Blot using polyclonal S protein-specific antibody (A) or PreS1-specific mouse serum (B). rec. HBsAg: recombinant S protein of HBsAg. (C) Cells were transfected with the indicated amounts of single expression vectors or mixtures thereof. S protein expression was analyzed by ELISA in supernatants of cells 72 h after transfection.</p

Kinetics of HBV antigen-specific humoral immune responses in pigs.

<p>Pigs were immunized with SAINT-18 (Ctrl.), a low, mid or high dose of SAINT-18-formulated MIDGE-Th1 vectors encoding the S protein (low S, mid S, high S), a high dose of SAINT-18-formulated MIDGE-Th1 vectors encoding the L protein (high L) or a human dose of Engerix-B on days 1, 29 and 57 (↓). Serum samples were collected on various test days and analyzed by ELISA for total S protein-specific antibodies (A), PreS1-specific IgG (B), S protein-specific IgG1 (C) and IgG2 (D). Data points represent mean values for all animals in each group (n = 3–5). For graphical purposes, samples without a PreS1-titer were set to 10 in (B). Statistical analysis is presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0101715#pone.0101715.s001" target="_blank">Tables S1</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0101715#pone.0101715.s004" target="_blank">S4</a>.</p