{HEAD ~ A preferred polyvalent agent} is {TAIL ~ an IgM}, and enhanced cell wounding and killing can be provided by the addition of a crosslinking agent 
is
{ HEAD ~ A preferred polyvalent agent } is { TAIL ~ an IgM } , and enhanced cell wounding and killing can be provided by the addition of a crosslinking agent
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH