Figure 3.

(a) NAb responses against wild-type virus and mutant viruses generated by mice infected with LCMV-WE and first-generation nAb-escape virus V1 or V2 (2 × 10⁴ pfu). DBA/2 mice were infected with 2 × 10⁴ pfu of LCMV-WE, mutants V1 or V2 (as indicated in the figures) and nAb against all mutant viruses, and LCMV-WE was measured in the sera at the indicated time points. Mean values with standard deviation of two independent assays are shown. (b) Induction of cross-reactive nAb is dose dependent (200 pfu). DBA/2 mice were infected with 200 pfu of LCMV-WE wild-type or first-generation nAb-escape mutant V1 or V2. Fifty days after infection, all mice were boosted with 200 pfu of the same virus with which they were initially infected. NAb in the sera (SV1 and SV2) was measured against the infecting virus and all other first-generation escape viruses (V1–V6). Mean values of two mice are shown. Day 0 represents the time point of primary infection. Gray symbols show neutralization response against the infecting virus.