<prompt> Which of the following is a pan-T lymphocyte marker?CD 2CD 3CD 19CD 25  <response>: Antigen Designation Normal cellular distribution Primarily T-cell associated CD 1 Thymocytes and Langerhans cells CD3 Thymocytes, mature T cells CD4 Helper T cells, subset CD5 T cells and a small subset of B cells CD8 Cytotoxic T cells, subset of thymocytes, and some NK cells 