NK cells mediate antibody-dependent cellular cytotoxicity primarily through which surface receptor?

NK cells mediate antibody-dependent cellular cytotoxicity primarily through which surface receptor?

• A. CD16
• B. CD3
• C. CD28
• D. CD4

Answer: (A)

Antibody-dependent cellular cytotoxicity by NK cells uses the Fc receptor to recognize antibodies bound to target cells. The receptor is CD16, also known as FcγRIII, which binds the Fc portion of IgG on coated targets. This engagement activates the NK cell and triggers release of perforin and granzymes to kill the target. The other receptors listed are not involved in ADCC: CD3 is part of the T-cell receptor complex, CD28 provides co-stimulatory signals for T cell activation, and CD4 is a helper T cell co-receptor. Hence, CD16 is the mediator of NK cell–driven ADCC.

Antibody-dependent cellular cytotoxicity by NK cells uses the Fc receptor to recognize antibodies bound to target cells. The receptor is CD16, also known as FcγRIII, which binds the Fc portion of IgG on coated targets. This engagement activates the NK cell and triggers release of perforin and granzymes to kill the target. The other receptors listed are not involved in ADCC: CD3 is part of the T-cell receptor complex, CD28 provides co-stimulatory signals for T cell activation, and CD4 is a helper T cell co-receptor. Hence, CD16 is the mediator of NK cell–driven ADCC.