(A and B) HBVEnvRag1^–/– mice were treated (tx) or not (untx) with clodronate liposome (Clod) on days –1, 2, 5, 8, and 11 and adoptively transferred on day 0 with WT splenocytes (n ≥ 5). (A) Plasma ALT. (B) Percent mice with circulating HBsAg. (C) HBV-specific T cell responses, identified by IFN-γ ELISpot, using liver-derived lymphocytes from clodronate-treated or untreated HBVEnvRag1^–/– mice 4 months after transfer. Data are pooled from n ≥ 4 mice. Pool 0 denotes no peptide; solid and dotted lines denote baseline IFN-γ levels for untreated and clodronate-treated, respectively; arrowheads denote a positive response ≥2× that of baseline. (D) Il21 mRNA expression levels in liver-derived lymphocytes from untreated and clodronate-treated adult HBVEnvRag1^–/– mice, untreated adult Rag1^–/– mice, and untreated young HBVEnvRag1^–/– mice 8 days after transfer, determined by RT-PCR (n ≥ 2). Data are representative of 3 (A, B, and D) or 2 (C) independent experiments. (E–G) Images (original magnification, ×10) from untreated and clodronate-treated HBVEnvRag1^–/– liver stained for (E) macrophages (green; F4/80) and nuclei (blue; DAPI) before adoptive transfer (day 0) or for F4/80 (green), DAPI (blue), and either CD4 (red; F) or B220 (red; G) 8 days after transfer. (H) 15 random frames from each section of n ≥ 3 mice per group were scored by an unbiased pathologist for number of parenchymal CD4⁺, CD8⁺, and B220⁺ lymphocyte clusters per frame (≥2 cells within 15 μm). Scale bars: 30 μm. **P < 0.01, unpaired 2-tailed Student’s t test.