Identify which of the following describes how antigen processing and presentation of self antigens ...

Identify which of the following describes how antigen processing and presentation of self antigens by thymic epithelial cells differs from that of antigen-presenting cells in peripheral tissues. (Select all that apply.)
 
  a. Thymic epithelium expresses MHC class I molecules but not MHC class II molecules.
  b. Thymic epithelium uses cathepsin L for proteolytic degradation of self proteins.
  c. Thymic epithelium expresses MHC class II molecules but not MHC class I molecules.
  d. Thymic epithelium uses the transcription factor AIRE to activate thymic expression of tissue-specific genes.
  e. Thymic epithelium expresses transcription repressor protein FoxP3.