Schematic model description.
(A) KIRs and MHC molecules are implemented as bitstrings. The receptor-ligand recognition is modeled via complementary matching. Here, the longest adjacent match is 6 bits long, and when the length of this match exceeds the threshold , the MHC molecules can be recognized by the KIR. (B) Description of the viral evasion mechanisms. The wild type virus can evolve MHC-downregulation and a decoy ligand for KIRs. The immune escape of the virus after evolution of the immunoevasive mechanisms is modeled by decreasing the clearance probability . The arrow-headed lines indicate the activation of the T cell or the NK cell, whereas the bar-headed lines indicate their inhibition.