They help in early fighting of viral infections and cancer with the help of a battery of activating receptors such as CD16, C-type lectin-binding receptors,NKp80 (a marker of maturity expressed by functionally mature NK cells present in the secondary lymphoid tissue (SLT and PB), NKG2D and CD94/NKG2C heterodimer, natural cytotoxicity receptors (NCR; NKp46, NKp44, NKp30), the nectin binding adhesion molecule, CD226/DNAM1 (DNAX Accessory molecule 1), activating killer cell immunoglobulin-like receptor (KAR), and the SLAM-related receptors (SRR) NTB-A, 2B4, and CRACC [35, 44]. This evidence concerns the gene CD226 and viral infectious disease.