{HEAD ~ The switch region} and membrane exons of {TAIL ~ the invention} may comprise a human gamma 2 constant region and the secreted constant region exons are from a human gamma 1 or a human gamma 4 constant region 
of
{ HEAD ~ The switch region } and membrane exons of { TAIL ~ the invention } may comprise a human gamma 2 constant region and the secreted constant region exons are from a human gamma 1 or a human gamma 4 constant region
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL 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