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