The immune system

Antibodies are an integral part of your body’s immune system. There are different kinds of antibodies, but all are necessary to the immune system to fight foreign bacteria and viruses.

Your immune system is composed of organs, cells, and chemicals that all work together to fight infections that threaten your body. In addition to antibodies, important parts of the immune system include white blood cells, the complement system and the lymphatic system, the spleen, the thymus, and bone marrow.

Your immune system is extremely effective. By creating certain targeted, tailor-made white blood cells, it adapts, altering in response to every bacteria and virus you encounter. These changes allow the immune system to quickly defeat infections if they make their way into your body again. A strong immune system will destroy foreign threats before they can multiply and make you ill.

There are certain infections that you’ll fight over and over again because there are so many different versions of the virus. Illnesses like the flu and common cold come in many "models," each vulnerable to its own unique antibodies. So, when you catch the flu you don’t gain immunity against all the other versions of the flu.

The immune system can be overactive or underactive. Overactivity might look like an allergic or autoimmune disease. Underactivity, also known as immunodeficiency, can have genetic causes, can result from treatments like medications or chemotherapy, or can occur after contracting another disease.

Antibodies, antigens, and the immune system

Antibodies are proteins made by your immune system to try and protect you. Antibodies are created when your immune system reacts to toxins, pollen, and infectious organisms. Your body is constantly making antibodies, so it has a constant supply ready to fight thousands of different threats.

In the immune system, antibodies work against antigens. These are infections and the poisonous substances that they may produce. Antibodies react to antigens either on the surface of infected cells or in the substances they produce. Antibodies leave a mark that flags these cells as foreign and dangerous—this lets other antibodies know a foreign cell needs to be destroyed. The immune system's antibodies wipe out the infection, as well as other health-threatening cells, proteins, and chemicals.

Antibodies and immunoglobulins

Immunoglobulins function similarly to antibodies, but they’re proteins found in your blood, tissues, and other fluids. There are five main classes of immunoglobulins that work together to carry out immune responses. An immunoglobulin deficiency can be the result of any kind of disorder that weakens the immune system. When this occurs the immunoglobulins that typically fight bacteria will either be completely missing or present in reduced numbers.

Immunoglobulin therapy is used to help you if you’re unable to make enough on your own or if your natural immunoglobulins don’t function correctly. Speak with your healthcare provider to learn more about immunoglobulin therapy if you have an immune condition that might benefit from specialized attention.


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Active antibodies

Active immunization occurs when foreign molecules are introduced into your body and your immune system reacts by creating unique tailored antibodies specifically for this target. Vaccines create active antibodies by inserting a concentration of infectious cells into your body. Usually, vaccines are treated with heat or chemicals to leave the cells unable to actually make you sick. A vaccine is a sort of trick for training your immune system to recognize a disease without having to get sick first; it creates active antibodies for an infection, but there’s no real danger from the "infectious" cells.

This method works because active immunization happens naturally. Vaccines use the body's own natural defenses. Normally when you come into contact with new bacteria and your body doesn’t have any passive antibodies ready to defend you, your immune system will do what it’s meant to do. It develops new customized antibodies tailored exactly to defeat the new attacker. These new antibodies will be ready to respond next time this bacteria makes its way into your body. Vaccines introduce safe "stand-ins" for the real disease cells, allowing your immune system to develop antibodies without risking the real illness. Essentially vaccines train your immune system with "stunt doubles."

Passive antibodies

Passive immunization happens when pre-made antibodies are given to you so that your body doesn’t need to make them. Passive antibodies are fast-acting, but they don’t last long. They are broken down quickly, and there is no natural way to produce more to replace them. These kinds of antibodies are helpful when your immune system needs antibodies quickly after exposure to infection.

More than the immune system

In addition to antibodies and your immune system, your body has other defenses against foreign infections:

  • Your skin. It provides a waterproof shield and makes oil that kills bacteria.
  • Your lungs. Mucus, also known as phlegm, collects unfamiliar substances. Tiny hairs, also known as cilia, help push the mucus up so you can cough it out.
  • Your digestive tract. It has a mucus lining that houses antibodies. The stomach’s acid kills many bacteria and viruses.

Protect your body

Those with weakened immune systems and immunoglobulin deficiencies are more likely to get infections, diseases, disorders, and allergic reactions. To learn how you can help your antibodies and immune system protect your body, get in touch with your healthcare provider.


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Medically Reviewed on 11/29/2021
Better Health Channel: "Immune system explained."

My-MS: "Immune Antibodies."

News Medical: "What is an Antibody?"