Expression of D^d-ζ in transgenic mice. Fresh splenocytes from the indicated strains were stained with anti-CD3 or anti-B220 and anti-D^d (34-2-12) mAbs and evaluated by flow cytometry. Represented are the parental FVB strain, the 3604 strain (MHC-D^d), and 2 D^d-ζ homozygous transgenic strains, 6657 and 130.