Figure 5

iSEC1 is selectively expressed by secretory cell lineages among intestinal epithelial cells.

(a) Cells isolated from the jejunum epithelium were stained with anti-CD45 and anti-iSEC1, and CD45⁻iSEC1⁺ (P) and CD45⁻iSEC1⁻ (N) cells were separately sorted, and subjected to quantitative RT-PCR analysis for the expression of indicated mRNAs (mean ± SEM, n = 3) and to cytoplasmic staining for indicated proteins. (b) CD24⁻iSEC1⁺ (SP) and CD24⁺iSEC1⁺ (DP) fractions of CD45⁻ cells in the jejunum epithelium were separately sorted, and subjected to the RT-PCR analysis as shown in a (mean ± SEM, n = 3). (c) Mice were treated with intraperitoneal injection of fluorescent-labeled anti-iSEC1 or control antibody, and the jejunum was isolated and analyzed for iSEC1 expression under confocal fluorescence microscope. Upper panels show longitudinal views of villi and crypts while lower panels display transverse views of crypts. iSEC1-positive cells were stained in blue. Data shown in a–c are representative of three independent experiments. ***p < 0.001.