T-cell receptors

T cells possess a CD3 complex composed of e chains along with two disulphide-lined glycoprotein chains, either ab or gd, and the CD3 zeta chain¹.

ab T-cells are of two types: CD4 positive and CD8 positive. CD4 positive "helper T cells" are more numerous, as are their lymphomas. Among CD4 positive T-cells, there are two groups. Th1 cells secrete interleukin (IL)-2 and interferon g but no IL-4, 5 or 6; they provide help to other T-cells and to macrophages. Th2 cells secrete IL-4, 5, 6 and 10; they provide help to B-cells in antibody production.

gd T-cells constitute about 5% of T-cells and are found in the splenic red pulp and intestinal and other epithelia; these sites are more commonly affected by gd T-cell lymphomas. They are negative for CD4 and CD5; most are negative for CD8.

NK cells express the e chain of CD3, which is recognised by polyclonal antisera to CD3. They also may express CD2, CD7, CD8 CD56 and CD57, all expressed by some T-cell subsets. In addition, they are positive for CD16, not usually expressed by T-cells.

T-cells and NK-cells both express perforin, granzyme B and T-cell intracellular antigen (TIA)-1.

References

⁰ World Health Organization Classification of Tumours, Tumours of the haematopoietic and lymphoid tissues, IARC Press 2001, page 192.

¹ Clevers H, Dunlap S,Terhorst C The transmembrane orientation of the epsilon chain of the TcR/CD3 complex. Eur J Immunol 1988; 18:705-10

This page last revised 17.12.2002.

©SMUHT/PW Bishop