Which of the following cell surface markers is required for lysis of IgG-coated target cells (antibody-dependent, cell-mediated cytotoxicity, or ADCC) by natural killer cells?

CD16 is a cell surface marker used to identify natural killer (NK) cells (lymphocytes lacking most T- and B-cell markers). CD16 is an Fc receptor for IgG, allowing the NK cells to bind to the coated target cell during ADCC, facilitating lysis. Also know: CD3 is a five-polypeptide cluster that represents the non-variable pa of the T-cell receptor complex. The variable pa is able to rearrange itself to adapt to specific antigens. Natural killer cells are CD3-negative. CD19 is a B-cell marker. It is a signal-transducing molecule that is expressed in early B-cell differentiation. NK cells are negative for CD19. C21 is also a B-cell marker. It is a complement receptor, and is also the same receptor the Epstein-Barr virus uses to bind to cells during infection. Ref: Levinson W. (2012). Chapter 58. Cellular Basis of the Immune Response. In W. Levinson (Ed), Review of Medical Microbiology & Immunology, 12e.