providing a retainer with a plurality of compartments, wherein {TAIL ~ a first compartment} comprises a first antibody and a second compartment comprises {HEAD ~ a second antibody} 
providing a retainer with a plurality of compartments , wherein { TAIL ~ a first compartment } comprises a first antibody and a second compartment comprises { HEAD ~ a second antibody }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD