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