In the thymus, thymic stromal cells(TSCs) are interconnected into a network structure. These cells carry a large number of surface molecules and can secrete a variety of thymic hormones and cytokines, which provides a suitable microenvironment for the development and maturation of thymocytes. The types of TSCs include ( ). A: epithelial cell B: macrophage C: dendritic cell D: neutrophil

能分泌类固醇激素的是： A: nephron B: pancreas islet C: corpus luteum D: thymic corpuscle E: renal corpuscle

Which of the following cells constitutively express MHC class II molecules? ( ) A: macrophage B: dendritic cell C: Langerhans cell D: B cell E: thymic epithelial cell