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