mRNA expression analysis: Mouse Cd94 and Nkg2a mRNAs were detected in splenocytes isolated from wild-type mice, while human CD94 and NKG2A mRNAs were detected in homozygous B-hCD94/hNKG2A mice. Protein expression analysis: Human CD94 and NKG2A proteins were detected in homozygous B-hCD94/hNKG2A mice, but not in wild-type mice. Immune cell analysis: CD94 and NKG2A humanization does not change the overall development, differentiation or distribution of spleen, lymph node (data not shown), and blood (data not shown) immune cells in B-hCD94/hNKG2A mice. In vivo efficacy of an anti-human NKG2A antibody: Anti-human NKG2A mono- and combination therapy controlled B-hHLA-E MC38 tumor growth in B-hCD94/hNKG2A mice.