Fig 5. A2a receptor agonist enhances Pneumovax 23 responses in young mice.

Young (3-week-old) WT mice were immunized i.p. with 10 μg of Pneumovax 23 and were subsequently treated daily with CGS 21680 or vehicle only DMSO (control) for 4 weeks as described in methods. Sera were analyzed by ELISA for anti-PPS3 specific Abs at day 0, 7, 14 and 28 after vaccination. On day 28, mice were challenged by i.p. injection of S. pneumoniae (5x10³ CFU). (A) Anti-PPS3 IgM and IgG3 OD (450–570) readings are shown (means ± standard errors are shown; *: p<0.05; **: p<0.01 by Student’s T test). (B) IgG3 mean reciprocal titers at day 7, 24 and 28 showing individual mice (means ± standard errors are shown; *: p<0.05; by One-way ANOVA). (C) Survival of infected mice (*: p≤0.05 by log-rank test; n.s.: p>0.05; survival was compared to non-vaccinated mice unless indicated by a bracket).