Receptor-specific staining of lymphocytes with reversible Fab Streptamers®
Fluorescent Fab Streptamers®, adducts of Strep-tagged
Fab fragments (Fab-Streps)
and Strep-Tactin® PE or APC,
are directed against cell surface markers including those of T cells (CD3, CD4, CD8), memory T cells (CD8, CD62L, CD45RA-), regulatory T cells (CD4, CD25, CD45RA) and B cells (CD19).
Cell staining procedure
1) Fab-Streps (Strep-tagged Fab fragments) are multimerized with Strep-Tactin® attached to a fluorochrome to generate multimers with high binding avidity. These multimers are directed to the respective cell surface marker(s) and are thus determined for staining of the target cell (Fig.1).
Fig. 2: Target cells are selected by a Fab Streptamer®.
After staining and fluorescence assisted sorting, the Strep-Tactin®
complex is removed from the target cells by the addition of biotin under
physiological conditions at low temperatures (4°C). The monomeric low affinity Fab-Strep molecules are then
dissociated completely from the cell surface by two short washing steps. The
isolated cells are phenotypically and functionally undistinguishable from
non-treated cells and predestined for clinical use.