CD21

CD21, also known as complement receptor 2, is a protein found on the surface of certain immune cells, particularly B cells. It helps these cells recognize and respond to pathogens by binding to parts of the complement system, which enhances immune responses. CD21 plays a key role in shaping how the immune system identifies and fights infections, and it's involved in processes like antibody production and immune regulation. Its proper function is essential for a healthy immune response, and abnormalities can be linked to immune disorders.