FIG 3.
Comparison of immune responses to URT and LRT-plus-URT MuHV-4 infections. (a) BALB/c mice were infected i.n. with MuHV-4, either under anesthesia (104 PFU in 30 μl [L]) or without anesthesia (105 PFU in 5 μl [U]). Sera and nasal washes were obtained in either the acute (day 10) or the convalescent (day 30) phase and assayed for MuHV-4-specific antibody by ELISA. Antibody titers are expressed relative to a standard immune serum pool assayed in parallel. Each bar shows the mean ± SEM of 6 mice. The baseline corresponds to the lower limit of assay sensitivity. (b) BALB/c mice were infected as for panel a and assayed for virus-specific AFCs in different lymphoid sites by ELIspot. The dashed line shows the limit of assay sensitivity (50 AFCs/organ). The bars show means ± SEM of 6 mice. URT infection gave significantly higher day 10 (d10) SCLN responses than LRT-plus-URT infection for all isotypes (P < 0.05), significantly lower spleen responses for all isotypes except IgA (P < 0.01), and significantly lower day 30 BM responses for IgG2a (P < 0.01), but not other isotypes (P > 0.1).