T lymphocyte (T-cell, thymocyte)

Introduction

Produced in the thymus from blood-borne progenitors from bone marrow & fetal liver. Immature thymocytes accumulate beneath the thymic capsule, then migrate inward through the cortex, corticomedullary junction to the medulla, undergoing proliferation & differentiation. Mature, self-tolerant MHC-restricted T cells are exported to the periphery to seed/replenish the peripheral T cell supply.

Pathology

Surface markers:

• T helper: CD3, CD4
• T cytotoxic: CD3, CD8
• naive/resting T cells: CD3, CD4 or CD8, CD45RA
• memory/activated T cells: CD3, CD4 or CD8, CD45RO

Pool size:

• CD4 cells: 2 x 10E11, 1/2life = 156 days
• CD8 cells: 1 x 10E11, 1/2life = 167 days

see ARUP consult

More general terms

• lymphocyte

More specific terms

• cytotoxic (suppressor) T cell (CD8+, CTL)
• EL 4 cell
• helper T cell (T4 lymphocyte, CD4+)
• Jurkat cell
• Lutzner cell (mycosis cell)
• mucosal-associated invariant T cell (MAIT cell)
• regulatory T cell
• Sezary cell

Additional terms

• T cell markers