FIG 6.
B cell response to URT influenza virus infection. (a) BALB/c mice were infected i.n. with influenza virus A/X31 (3 × 106 PFU in 5 μl; no anesthesia) and assayed by ELISA 7 or 13 days later for virus-specific antibody in sera and nasal washes. Each solid line shows the absorbance curve for 1 infected mouse. The dashed line represents a naive control. Dilutions were from 1/100 for sera and from 1/3 for nasal washes. (b) The same mice were analyzed for virus-specific AFCs in SCLN and NALT by ELIspot. Each point shows the result for 1 mouse. ×, mean.