Figure 2
From: MZB1 enables efficient interferon α secretion in stimulated plasmacytoid dendritic cells
Mzb1−/− pDCs show a reduced expansion of the ER and intracellular retention of IFNα. (A) Electron microscopy (EM) analysis of Mzb1+/+ and Mzb1−/− pDCs that were unstimulated or stimulated with CpG A for 24 h (left-hand panels). Red arrows indicate the ER. The quantification of the sphericity index of the ER, as the ratio of the width to the length of the ER, is shown in the right-hand panels. Each dot is a biologically separate sample with approximately 50 different cells imaged for each sample. Statistical difference between the mean was analysed by an unpaired two-tailed Student’s t-test. *P ≤ 0.05. Error bars show SD. ns, non-significant. (B) Intracellular and secreted IFNα levels of CpG A-stimulated (24hrs) Mzb1+/+ and Mzb1−/− pDCs, as determined by ELISA of lysates and supernatants of 105 cells, respectively. Each dot represents pDCs derived from the bone marrow of individual mice. Data from two separate experiments were included in the analysis. Statistical difference between the mean was analysed by an unpaired two-tailed Student’s t-test. *P ≤ 0.05, **P ≤ 0.005. Error bars show SD. (C) Co-immunoprecipitation assay to detect the interaction of MZB1 with IFNA2. Lysates of K46 B cells expressing HA-tagged IFNA2 were incubated with an anti-Mzb1 monoclonal antibody or an IgG control. MZB1 and IFNA2 were detected by immunoblot analysis with MZB1- and HA-specific antibodies, respectively. Uncropped blots are shown in Supplementary Fig. S3C.
