Antibodies, also known as immunoglobulins, are protective proteins produced by your immune system to target and remove foreign substances (antigens) from your body. Several types exist, each with specific roles.
The Five Main Antibody Types
The human body produces five main types of antibodies:
- IgG: The most common antibody, present mostly in blood and tissue fluids. It plays a crucial role in long-term immunity. There are even subclasses within IgG (IgG1, IgG2, IgG3, and IgG4).
- IgA: Found predominantly in mucous membranes (lining respiratory and gastrointestinal tracts), providing protection against pathogens entering the body through these surfaces.
- IgM: Usually the first antibody produced during an immune response. It is effective at activating the complement system (part of the immune system).
- IgE: Primarily involved in allergic reactions and defense against parasites.
- IgD: Its exact function remains less understood, though it's believed to play a role in B cell activation.
Examples of Antibodies in Action
Specific examples of antibodies highlight their diverse functions:
- Monoclonal antibodies (mAbs): These are laboratory-produced antibodies designed to target specific antigens, like those on cancer cells. Examples include trastuzumab (Herceptin) and rituximab (Mabthera) used in cancer treatment. Some mAbs help the immune system attack cancer cells, while others block signals that tell cancer cells to grow. Antibody-drug conjugates (ADCs), like Brentuximab vedotin, combine mAbs with chemotherapy drugs for enhanced efficacy.
Antigens Antibodies Target
Antibodies target a wide range of antigens, including:
- Microorganisms (bacteria, fungi, parasites, and viruses)
- Chemicals
The examples above demonstrate the versatility and importance of antibodies in maintaining health and fighting disease.
