Regulation of CD94/NKG2A expression in vivo. (A) A total of 5 × 105 purified naive 2C CD8+ T cells (Thy1.1) were transferred intravenously into B6 mice; and 1 day later, the mice were injected intraperitoneally with 5μM SIYR peptide with or without poly I:C (10 μg), LPS (5 μg), or CpG ODN (1 μg) or a combination of both poly I:C plus either LPS or CpG ODN. (B) A mixture of purified naive 2C CD8+ and OT-II CD4+ T cells (2 × 105 for 2C and 1 × 106 for OT-II; all Thy1.1) was transferred intravenously into B6 mice; and 1 day later, the mice were injected intraperitoneally with SIYR (5μM) plus ovalbumin323–339 peptide (OT-IIp; 10μM) with or without CTLA4Ig (50 μg) or IL-4 (1 μg)/anti-IL-4 monoclonal antibody (20 μg) complexes (injected daily for 2 consecutive days). *P < .01. **P < .005. (C) A total of 5 × 105 purified naive 2C CD8+ T cells (Thy1.1) were cotransferred intravenously with in vitro-stimulated differentiated OT-II CD4+ T helper subsets, Th0, Th1, and Th2 (1 × 106; Thy1.1) into B6 mice; on the same day, the mice were injected intraperitoneally with 5μM SIYR and 10μM ovalbumin323–339 peptide. (D) A total of 5 × 105 purified naive 2C CD8+ T cells (Thy1.1) were transferred intravenously into B6 mice; and 1 day later, the mice were injected intravenously with 2 × 106 LPS-matured bone marrow–derived DC pulsed with 10μM SIYR peptide (BMDC-SIYRp) with or without 2 μg CsA or 0.2μM FK506 (injected daily for 3 consecutive days). *P < .05. **P < .005. (E) A total of 5 × 105 purified naive WT or CnAβ−/− OT-I CD8+ T cells (Thy1.1) were transferred intravenously into B6 mice; and 1 day later, the mice were injected intravenously with 2 × 106 BMDCs pulsed with 10μM SINF peptide (BMDC-SINFp) either with or without intraperitoneal injection of IL-2 (0.5 μg)/anti-IL-2 monoclonal antibody (10 μg) complexes. *P < .005. **P < .05. ***P < .05. (A-E) On day 4 after antigenic stimulation in vivo, pooled spleen and lymph node from the recipient mice were analyzed for expression of NKG2ACE on donor 2C (A-D), OT-II (B-C), and OT-I (E) cells by flow cytometry. The percentages of cells in the respective regions (B-E) are indicated. (A-E) Data are representative of 2 or 3 independent experiments (A-B,D-E; mean ± SD from 4 or 5 mice per group).