The immunization of the LiPABP genetic combined vaccine induces a predominant Th1-biased response against the LiPABP family in BALB/c mice.

<p>Mice (n = 16 per group) were immunized three times with phosphate saline buffer (saline), with the pcDNA3 plasmid or with the LiPABP1 + LiPABP2 + LiPABP3 combined genetic vaccine. The presence of anti—LiPABP1, anti-LiPABP2, anti-LiPABP3 and anti-LiPABPs IgG1 and IgG2a immunoglobulins were individually determined four weeks after the last doses. Sera were assayed from 1/100 to 1/820,000 and horseradish peroxidase-conjugated anti-mouse IgG1 or IgG2a were used as the secondary antibodies at 1/2,000 (A). Results are shown as whisker (min to max) plots. * (<i>P</i> < 0.05) and ** (<i>P</i> < 0.01) statistical differences between IgG1 and IgG2a reactivity values evaluated by the Mann-Whitney test. At the same time <b>s</b>pleen cell cultures were established from eight mice. Splenocytes (5 x 10⁶ cells/ml) were cultured for 72 h at 37°C, 5% CO₂ in the presence of parasite LiPABP1, LiPABP2 and LiPABP3 as independent stimuli (12 μg/ml) or a mixture of the three proteins (12 μg/ml total protein, 4 μg/ml each one). As background control, parallel cultures were maintained without stimulation (Medium). The levels of IFN-γ, IL-10 and IL-4 were determined by capture ELISA in culture supernatants (B). Each bar represents the mean ± standard deviation (SD) of data taken from eight individual mice. ⁺ <i>P</i> < 0.05, ⁺⁺ <i>P</i> < 0.01 and ⁺⁺⁺ <i>P</i> < 0.001 significant differences between LiPABP vaccinated and saline control mice; ** <i>P</i> < 0.01 and *** <i>P</i> < 0.001 significant differences between LiPABP vaccinated mice and pcDNA3 immunized control mice (Student T-test). Results are representative of two independent experiments.