Fig. 3.

Effective boosting of respiratory syncytial virus (RSV)-specific interferon (IFN)-γ-secreting CD8 T cells in lungs and spleens of mice primed as neonates. Analysis of the neonatal primary response in the lung (a) and spleen (b) is shown. Mice primed as adults or neonates were rechallenged with RSV during adult life 7 weeks post-priming (c and d). Mice previously naive were challenged once with RSV. At the times indicated post-secondary challenge with RSV (or primary challenge for the naive group, and neonatal primary response), RSV peptide-specific IFN-γ-secreting cells in lung (a and c) and spleen (b and d) were detected by enzyme-linked immunospot assay (ELISPOT). Values represent means of at least five mice ± standard deviation. Insignificant differences between adult-primed and neonatally primed groups are shown for day 4; *P = 0·314 (lung) and **P = 0·280 (spleen) by Student's t-test. The data shown are representative of two independent experiments.