Said additional constant region segment comprises {TAIL ~ a switch region} and {HEAD ~ human constant region coding segment}, wherein the constant region coding segment is operably linked to a switch region that it is not normally associated with, i.e., a non cognate switch region 
Said additional constant region segment comprises { TAIL ~ a switch region } and { HEAD ~ human constant region coding segment } , wherein the constant region coding segment is operably linked to a switch region that it is not normally associated with , i.e. , a non cognate switch region
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD 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 OTH OTH OTH OTH