One is {TAIL ~ a cell delivery agent} for delivering a biologically active protein or peptide to {HEAD ~ a cell} as described above 
One is { TAIL ~ a cell delivery agent } for delivering a biologically active protein or peptide to { HEAD ~ a cell } as described above
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH