Proximity selection using natural ligands

In many situations it is not possible to obtain an existing antibody specific to the antigen in question, but another lype of known binding molecule, such as a natural ligand may be available. A number of natural ligands have been used as 

Proximity selection using a natural ligand on cells in suspension 

Prepare approx 1 x 10 to 1 x 10 cells in solution in an approx, volume of 100 p.1 PBS containing 3% skimmed milk powder and incubate for 1 h at room temperature. 

Add biotinylated ligand at an appropriate concentration (e.g. for selections on CD4 cells using biotinylated MIP-la the hgand was added to a final concentration of 375 nM) and incubate for 1 h at room temperature. 

Gently wash the cells by low speed centrifugation with three changes of PBS. 

---

Proximity selection using a guide antibody on an adherent cell line 80 Proximity selection using a natural ligand on cells in suspension 82... 

---