In the transgenes of the invention, the non cognate switch region may be a switch region from {HEAD ~ a different species} than {TAIL ~ the constant region coding segment} 
In the transgenes of the invention , the non cognate switch region may be a switch region from { HEAD ~ a different species } than { TAIL ~ the constant region coding segment }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL