How does IVIG work?
The immune system recognizes and attacks foreign substances, called “antigens”. Antigens are molecules on the surface of viruses, fungi, or bacteria. Some non-living substances such as toxins, chemicals, and drugs can be antigens, too. For each new antigen encountered, the immune system forms a defense that is specific to that antigen, allowing the body to destroy it. Immunoglobulins are an important part of that defense. Each immunoglobulin attaches to its specific, matching antigen and makes it easier for phagocytes (a type of white blood cell which engulfs and digests antigens) to destroy the antigen. Binding of the immunoglobulin to an antigen also activates a set of proteins called the “complement” system, which ruptures bacteria and viruses. When the immune system is too immature (as in the case of a young infant) or does not otherwise have the ability to form its own antibodies, “passive immunity” can protect against infection. Passive immunity involves antibodies that are produ
