Figure 4.

CD8 depletion during vaccination rescues IL-15Rα expression by DCs. (A) B6 mice treated as shown in Fig 2A. Representative histograms showing IL-15Rα expression (black line) on DCs (Thy1.2-/IgM−/CD3−/CD11c+/MHCII+/CD11b+) and isotype staining (gray shaded area).Numbers listed indicate MFI. (B) CD11c+ DCs were magnetically purified from inguinal DLNs from B6 mice treated with IgG, CD8 depletion, or anti-IFN-γ (IFN-γ blockade; 500μg at day 0 and day 5) and analyzed for IL-15Rα expression as in (A). Cumulative bar graph of IL-15Rα expression by DCs. (C) Thymectomized C57BL/6 mice were CD8+ T cell depleted (500ug), rested for 14 days, and were reconstituted with PBS (No Txfr = No transfer), IFN-γ+/+ (C57BL/6), or IFN-γ−/− CD8+ T cells (4*10⁶). One day following reconstitution mice were OVA vaccinated (days 1, 6, and 11). IL-15Rα expression was analyzed from DCs isolated from the draining inguinal lymph nodes (day 15). Numbers listed indicate MFI. (D) B6 mice were vaccinated and depleted as in (A). IL-12 blocking antibody (250μg) was administered via intraperitoneal injection at days 0, 2, 4, and 5. Representative flow plot showing IL-15Rα expression by DCs. The mean and standard error for the absolute values presented in the representative flow plot: OVA = 851.3 ± 103.0, OVA + αCD8 = 1350 ± 69.2, OVA + αIL-12 = 1129 ± 87.8, and OVA + αCD8 + αIL-12 = 1320 ± 70.2. Statistical significance was determined using the absolute MFI values. All data shown are representative of results from 2–3 independent experiments with n=3–5 per group. *p < 0.05.