Which surface markers are typically present on NK cells?

Natural Killer (NK) cells are a type of lymphocyte crucial for the innate immune response, particularly in identifying and destroying virus-infected cells and tumor cells. The surface markers commonly present on NK cells include CD16 and CD56.

CD56, also known as Neural Cell Adhesion Molecule (NCAM), is a key marker that distinguishes NK cells from other types of lymphocytes, such as T cells and B cells. The presence of CD56 on NK cells indicates their role in various immune responses, including their ability to recognize and kill infected or transformed cells.

CD16, the low-affinity Fc receptor for IgG, enables NK cells to participate in antibody-dependent cellular cytotoxicity (ADCC). This mechanism allows NK cells to recognize and kill cells that are coated with antibodies, enhancing their role in the immune defense.

In contrast, other markers mentioned in the options do not characterize NK cells. For instance, CD3 is a marker found primarily on T cells, while CD14 is a monocyte marker, and CD19 is a B cell marker. Similarly, CD4 and CD8 differentiate between helper T cells and cytotoxic T cells, respectively. Thus, the combination of CD16 and CD56 is particularly representative of NK