Consideration of that question raises issues of complement fixation and the like, which then drives {HEAD ~ the selection} of {TAIL ~ the particular class} or isotype of antibody 
of
Consideration of that question raises issues of complement fixation and the like , which then drives { HEAD ~ the selection } of { TAIL ~ the particular class } or isotype of antibody
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH