Flow-cytometry platform

Whole blood samples were stained with CD8-PE antibody, and the expression of CD8 cells was analyzed by BD FACSCanto™ II flow cytometer. CD8 lymphocytes grouping were clearly observed.

Fig.1 Flow cytometry analysis of CD8 expression in lymphocytes of human peripheral

CD8 molecule is a glycoprotein exists on the surface of partial T cells, and its most important function is to assist T cell receptors (TCRs) in recognizing antigens and participating in T cell activation signal transduction. T cells expressing CD8 (CD8+T cells) typically differentiate into cytotoxic T cells (CTLs) after activation. The CD8 molecule can form two different dimers via the disulfide bond, which are ααhomodimer (CD8αα) and αβ heteromer (CD8αβ). Both theαchain and theβchain are transmembrane proteins and belong to immunoglobulins superfamily (lgSF). CD8 is a co-receptor for major histocompatibility complex I (MHC I) class molecules recognized antigens. The variable-resembling domain (V-set domain) of the CD8α chain interacts with the α3 domain of the heavy chain of MHC I class molecules, assisting TCR to recognize antigens presented by MHC I class molecules and enhancing the interaction between T cells and target cells. When CD8 binds to MHC I class molecules, its intracellular part can bind to tyrosine protein kinase p56^lck, and the activated p56l^lck catalyzes the phosphorylation of the immunoreceptor tyrosine-based activation motif (ITAM) of CD3 molecules, and then transducting the activation signal of T cells.

References

[1] CD8: Adhesion Molecule, Co-Receptor and Immuno-Modulator[J]. Cellular & Molecular Immunology, 2004.