Strep-Tactin(R) Magnetic Microbeads

Strep-Tactin(R) Magnetic Microbeads are microspheres covalently linked to Strep-Tactin(R). They are suitable for labeling antigen-specific cytotoxic T cells (MHC I Streptamer(R)) or surface marker-specific cells (Fab-TACS(R)/Nano-TACS(R)). To target specific cells, MHC I complexes, low affinity Fab fragments or nanobodies fused to a Twin-Strep-tag(R) (MHC I-Streps, Fab-Streps or Nano-Streps) are required in addition to fluorescent Strep-Tactin(R). Strep-Tactin(R) multimerizes MHC I-Streps or Fab-/Nano-Streps, ensuring stable binding to cells. The resulting magnetic complexes can be used to label cells that are specific for the respective peptide-loaded MHC I molecule or for a selected surface marker. The addition of biotin reverses the multimerization and causes the dissociation of MHC I-Streps or Fab-/Nano-Streps from the cell surface. The complete removal of all labeling reagents permits serial positive selection as well as depletion steps and reserves the cells' full biological activity.