Properties and Function of different classes of Antibodies


Antibodies are specialized proteins that are produced by the immune system to fight against foreign substances that enter the body, such as bacteria, viruses, fungi, allergens, and toxins. These substances are called antigens and they have distinct molecules on their surface that can be recognized by antibodies. Antibodies bind to antigens with a specific shape and either destroy them directly or mark them for destruction by other immune cells and proteins.

Another word for antibody is immunoglobulin (Ig). There are five classes of antibodies or immunoglobulins: IgG, IgM, IgA, IgD, and IgE . They differ in their heavy chains, which have different amino acid sequences and constant domains. The heavy chains are labeled by Greek letters: gamma (γ), mu (μ), alpha (α), delta (δ), and epsilon (ε), respectively. The light chains are either kappa (κ) or lambda (λ) and they are identical within each antibody class.

Each class of antibody has a distinct structure, location, and function in the immune system. They can be found in various fluids and tissues of the body, such as blood, saliva, tears, mucus, breast milk, and intestinal secretions. They can also be expressed on the surface of B cells, which are specialized white blood cells that produce antibodies. Some antibodies can cross the placenta and protect the developing fetus from infections. Some antibodies can activate the complement system, which is a group of proteins that enhance the immune response. Some antibodies can mediate allergic reactions or protect against parasitic infections.

In this article, we will discuss the properties and functions of each class of antibody in more detail. We will also explain how they work together to provide immunity against various pathogens and diseases.