Antigen details
Specificity & Reactivity: The CD8 antigen is expressed on the 32-kilodalton (kd) subunit of a disulfide-linked bimolecular complex. The majority of peripheral blood CD8 + T lymphocytes expresses an heterodimer (Mr 32, 30 kd), while CD8 + CD16 + natural killer (NK) lymphocytes and CD8 +T-cell receptor (TCR)+ T lymphocytes express an ?homodimer (Mr 30 kd).
CD56 recognizes an extracellular immunoglobulin-like domain common to three molecular weight forms (Mr 120, 140, and 180 kd) of the neural cell adhesion molecule.
Clinical Applications: The CD8 antigen is present on the human suppressor/cytotoxic T-lymphocyte subset as well as on a subset of NK lymphocytes.15 The CD8 antigen is expressed on 19% to 48% of normal peripheral blood lymphocytes 16 and 60% to 85% of normal thymocytes. The CD56 antigen is present on approximately 10% to 25% of peripheral blood lymphocytes. It is present on essentially all resting and activated CD16 + NK lymphocytes and approximately 5% of CD3 + peripheral blood lymphocytes.
