What is the CD marker for FcγRII?

The correct answer is that the CD marker for FcγRII is CD32. FcγRII refers to one of the receptors for the Fc region of immunoglobulin G (IgG) antibodies, and CD32 is the designation given to this receptor. This receptor plays a critical role in the immune response by mediating various functions such as phagocytosis, antibody-dependent cellular cytotoxicity, and the regulation of immune cell activation.

Other choices include CD19, CD22, and CD45, which are markers associated with different immune functions. CD19 is primarily expressed on B cells and plays a role in B cell activation and development. CD22 is also a B cell-specific marker, involved in B cell signaling and regulation. CD45 is a common leukocyte antigen found on all nucleated hematopoietic cells and is important for signaling in various immune responses. Each of these markers serves specific functions and is associated with particular types of immune cells, highlighting why CD32 specifically identifies FcγRII.