Diseases, Conditions, Syndromes

Study shines light on longevity of COVID-19 immune response

By uniting research from eight cohorts across the U.S., a group of researchers has accelerated collection of data integral in answering questions about immune responses needed for long lasting protection from SARS-CoV-2. ...

Diseases, Conditions, Syndromes

Studies reveal key clues about COVID-19 immunity, immune recall

How does the immune system remember and recognize viral invaders it has encountered in the past? A trio of newly published studies of people infected with SARS-CoV-2, vaccinated against the virus, or both are providing tantalizing ...

Pediatrics

Q and A: A parents' guide to COVID booster shots for kids 5-11

With COVID-19 cases rising again in the Bay Area, parents have a new consideration for protecting their children this week: The Food and Drug Administration granted emergency use authorization Tuesday for kids ages 5-11 to ...

Diseases, Conditions, Syndromes

COVID booster needed for broad protection against omicron variants

A COVID-19 booster shot will provide strong and broad antibody protection against the range of omicron sublineage variants of the SARS-CoV-2 virus in circulation, two new studies using serum from human blood samples suggest.

Diseases, Conditions, Syndromes

Scientists explain what makes COVID-19 antibody 'J08' so potent

Last year, scientists at Scripps Research and Toscana Life Sciences studied the blood of 14 COVID-19 survivors to find the most potent antibodies against the SARS-CoV-2 virus. One of the leading molecules that emerged—now ...

Diseases, Conditions, Syndromes

When to get a COVID-19 booster

If you recently had COVID-19, you may be wondering if you should delay getting your booster. We asked James Moy, MD, an immunologist in the Department of Internal Medicine at RUSH who is studying the antibody levels and duration ...

Diseases, Conditions, Syndromes

Mayo Clinic Minute: How to manage hay fever allergy symptoms

Don't be alarmed if you are experiencing seasonal allergies for the first time. While hay fever—also known as allergic rhinitis—often begins in childhood, more adults are being diagnosed, according to the Centers for ...

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Antibody

Antibodies (also known as immunoglobulins, abbreviated Ig) are gamma globulin proteins that are found in blood or other bodily fluids of vertebrates, and are used by the immune system to identify and neutralize foreign objects, such as bacteria and viruses. They are typically made of basic structural units—each with two large heavy chains and two small light chains—to form, for example, monomers with one unit, dimers with two units or pentamers with five units. Antibodies are produced by a kind of white blood cell called a plasma cell. There are several different types of antibody heavy chains, and several different kinds of antibodies, which are grouped into different isotypes based on which heavy chain they possess. Five different antibody isotypes are known in mammals, which perform different roles, and help direct the appropriate immune response for each different type of foreign object they encounter.

Although the general structure of all antibodies is very similar, a small region at the tip of the protein is extremely variable, allowing millions of antibodies with slightly different tip structures, or antigen binding sites, to exist. This region is known as the hypervariable region. Each of these variants can bind to a different target, known as an antigen. This huge diversity of antibodies allows the immune system to recognize an equally wide diversity of antigens. The unique part of the antigen recognized by an antibody is called an epitope. These epitopes bind with their antibody in a highly specific interaction, called induced fit, that allows antibodies to identify and bind only their unique antigen in the midst of the millions of different molecules that make up an organism. Recognition of an antigen by an antibody tags it for attack by other parts of the immune system. Antibodies can also neutralize targets directly by, for example, binding to a part of a pathogen that it needs to cause an infection.

The large and diverse population of antibodies is generated by random combinations of a set of gene segments that encode different antigen binding sites (or paratopes), followed by random mutations in this area of the antibody gene, which create further diversity. Antibody genes also re-organize in a process called class switching that changes the base of the heavy chain to another, creating a different isotype of the antibody that retains the antigen specific variable region. This allows a single antibody to be used by several different parts of the immune system. Production of antibodies is the main function of the humoral immune system.

This text uses material from Wikipedia, licensed under CC BY-SA