Figure 4. Hybrid resistance is compatible with licensing.

Depicted is the situation in a F₁ hybrid mouse expressing H2K^b and H2D^d which, for the sake of simplicity in this diagram, can only be recognized by Ly49C and Ly49A, respectively. Both Ly49A⁺ and Ly49C⁺ NK cells are licensed by host MHC class I alleles. However, since they are separately licensed, they manifest different reactivities against parental targets lacking one or the other MHC class I allele, as illustrated. To avoid clutter, activation receptors that trigger killing of susceptible targets are not shown.