Abstract
To determine why the H-2Dd antigen is expressed on the surface of transfected [mouse] cells at a rate several-fold higher than an analogously transfected H-2Ld molecule, both previously described and new H-2 hybrid genes were analyzed. These genes were constructed by exchanging domains between H-2 genes. Quantitative radioimmunoassay indicates that the region of the H-2Dd molecule responsible for its enhanced expression resides in the polymorphic N domain, the first domain of the mature class I molecule.