Figure 1.

(a) Schema of infection with LCMV-WE wild-type and the various nAb-escape mutants. (b) Transient or long-term control of LCMV-WE viremia in DBA/2 mice. Eight DBA/2 mice were i.v. infected with 2 × 10⁶ pfu of LCMV-WE. LCMV titers were measured in the blood by focus forming assays. In six of eight mice (S1-S6) LCMV reappeared in the blood by day 90 after infection. Two mice (S7 and S8) controlled LCMV for >170 days. (c) nAb against LCMV-WE and first-generation nAb-escape mutant viruses V1 and V2. Sera from LCMV-WE-infected mice (S1 and S2) were tested for nAb against LCMV-WE and the mutant viruses V1 and V2. All mice mounted a nAb response against LCMV-WE, but no nAb titers could be detected against the mutants in the mice in which they had arisen (<1 represents a titer <1:20). Gray symbols represent neutralization response against the infecting virus (LCMV-WE). (d) Sera from mouse 7 and 8 (S7 and S8) were able to neutralize not only LCMV-WE but also many of the mutant viruses V1-V6. (e) Sera from mice infected with LCMV-WE (S1 and S2), in which LCMV mutant V1 and V2 had emerged, were analyzed for cross-neutralization against mutant viruses (V1–V6).