T cell surface protein CD28
| T cell surface protein CD28 | ||
|---|---|---|
|
||
| CD28 bound to antibodies | ||
| other names |
TP44, T-cell-specific surface glycoprotein CD28 |
|
| Properties of human protein | ||
| Mass / length primary structure | 220 amino acids , 25,066 Da | |
| Identifier | ||
| External IDs | ||
T cell surface protein CD28 is a surface protein found in T cells and plasma cells , but not in immature B cells .
properties
CD28 is involved in the activation of T cells as a costimulator . CD28 binds CD80 and CD86 , surface proteins from the B7 family, which are expressed by antigen-presenting cells. Only when CD28 binds to its ligand in addition to binding the T-cell receptor can the T-cell be activated.
Intracellularly, CD28 can activate phosphoinositide-3-kinases . This kinase converts phosphatidylinositol-4,5-bisphosphate (PIP2) to phosphatidylinositol-3,4,5-trisphosphate (PIP3). PIP3 is required to activate phospholipase C -γ, an important enzyme in the TCR signaling pathway.
Furthermore, it was found that CD28 increases the formation of interleukin-4 and interleukin-10 in T cells when the T cell receptor is activated with co-stimulation by CD40L . The isoform 3 of CD28 enhances CD40L-dependent formation of NF-kB as well as MAPK8 and PAK2 in T-cells.
The antibody TGN1412 binds to CD28 and caused unforeseen serious adverse events in clinical studies in humans in six test subjects, but not in the previous animal experiments on macaques. Therefore, the further development of the drug approval of TGN1412 was stopped.
See also
Web links
Individual evidence
- ^ Lieping Chen, Dallas B. Flies: Molecular mechanisms of T cell co-stimulation and co-inhibition . In: Nature Reviews Immunology . 13, No. 4, March 8, 2013, pp. 227–242. doi : 10.1038 / nri3405 .
- ↑ Janeway's immunobiology , Ninthition. Edition, ISBN 0815345518 .
- ↑ MH Blotta, JD Marshall, RH DeKruyff, DT Umetsu: Cross-linking of the CD40 ligand on human CD4 + T lymphocytes generates a costimulatory signal that up-regulates IL-4 synthesis. In: Journal of Immunology (Baltimore, Md.: 1950). Volume 156, Number 9, May 1996, pp. 3133-3140, PMID 8617933 .
- ↑ SA Mikolajczak, BY Ma, T. Yoshida, R. Yoshida, DJ Kelvin, A. Ochi: The modulation of CD40 ligand signaling by transmembrane CD28 splice variant in human T cells. In: The Journal of experimental medicine. Volume 199, number 7, April 2004, pp. 1025-1031, doi : 10.1084 / jem.20031705 , PMID 15067037 , PMC 2211876 (free full text).