Some of the first step antibody binds to {HEAD ~ antigens} present at or near {TAIL ~ the body part}, and unbound first step antibody is washed away 
present at
Some of the first step antibody binds to { HEAD ~ antigens } present at or near { TAIL ~ the body part } , and unbound first step antibody is washed away
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH