T cell stimulation
Naive T cells require at least two signals for activation, proliferation and differentiation. The first signal is generated via the T cell receptor (TCR) and its MHC ligand. The second, most effective co-stimulatory signal is evoked by the interaction of the CD28 receptor of the T cell with its ligand CD80/86 (glycoprotein B7).
CD3/CD28 Streptamers® for T cell expansion
The in vitro generation of a large number of functional T cells is important for basic research as well as for therapeutic approaches. Commonly used stimulatory reagents for resting T cells are magnetic beads carrying αCD3 and αCD28 monoclonal antibodies.
The Streptamers® for cell expansion are novel reagents for polyclonal expansion of T cells:
- They are non-magnetic soluble protein complexes generated by multimerization of αCD3- and αCD28 Fab-Streps® with a Strep-Tactin® multimer.
- They are completely reversible reagents, i.e. they can be removed from the cells by the addition of biotin.
Reaction scheme of CD3/CD28 Streptamers® for T cell expansion
CD3- and CD28 Fab-Streps are multimerized via the soluble Strep-Tactin® multimere to generate the soluble Streptamer® for cell expansion. The subsequent biotin-induced dissociation of the reagents from the cells can be performed at any time point during stimulation, simply by the addition of biotin. The termination of stimulation can thus be precisely controlled.