FIG. 1.

Schematic representation of the experimental protocol used to infect and challenge woodchucks with liver-pathogenic (group A) and liver-nonpathogenic (group B) doses of WHV. In total, 12 WHV-naive, healthy animals were i.v. injected with low (nonpathogenic; 50 vge), medium (liver-pathogenic; 1.1 × 10⁶ vge), or high (liver-pathogenic; 1.1 × 10¹⁰ vge) doses of WHV/tm3 inoculum. (A) Animals in study group A (n = 4) were injected with either a high (1.1 × 10¹⁰ vge; n = 2) or medium (1.1 × 10⁶ vge; n = 2) dose of WHV. Animals developed classical, serologically detectable WHV infection and were challenged with a low (50 vge; n = 1) or medium (1.1 × 10⁶ vge; n = 1) dose of WHV/tm3 or injected with PBS. (B) Animals in study group B (n = 8) were initially injected with a 50-vge dose of WHV. All animals developed serum WHsAg and anti-WHc negative but WHV DNA reactive POI and were challenged or rechallenged with a low (50 vge; n = 5) or high (1.1 × 10¹⁰ vge; n = 4) dose of the same inoculum or injected with PBS. The animals from groups A and B were divided into subgroups according to the dose of WHV used for the challenge or rechallenge or injection with PBS, as described in detail in Materials and Methods. The groups and subgroups were named using the following designations: L, low virus dose (50 vge); M, medium virus dose (1.1 × 10⁶ vge); H, high virus dose (1.1 × 10¹⁰ vge); N, no virus (injection with PBS).