Complement component 3, often called C3, is an essential protein of the immune system. This protein plays a vital role in the body’s innate immune system, providing: the first line of defense against ...

It was called ‘complement’ because it aided the antibacterial activity of antibodies. However, it is now known that the complement system can be activated early in an infection without the presence of ...

The complement system is a key component of innate and adaptive immunity and therefore acts as a vital defense against invading pathogens. Deficiencies in the complement system are associated with ...

A complement C4 (also known as a complement component 4, or simply C4) is a test to measure the level of C4 proteins you have in your blood. These proteins play a role in how your immune system ...

TWO inborn errors of the complement system of man have been well documented: hereditary deficiency of the serum inhibitor of the activated first component of complement (C′1a) and hereditary ...

Long Covid patients suffer from chronic symptoms such as fatigue or shortness of breath. As researchers have discovered, this is to some extent due to a part of our immune system called the complement ...