{TAIL ~ These previously unseen peptides/proteins} may enter and associate with the empty major histocompatibility complex molecules of the surviving cells to form {HEAD ~ non naturally occurring species} of antigen associated antigen presenting cells, which then could be tested for their ability to confer to the recipient a beneficial immune system response 
{ TAIL ~ These previously unseen peptides / proteins } may enter and associate with the empty major histocompatibility complex molecules of the surviving cells to form { HEAD ~ non naturally occurring species } of antigen associated antigen presenting cells , which then could be tested for their ability to confer to the recipient a beneficial immune system response
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH