Immunoglobulins

Immunoglobulins, also known as antibodies, are proteins produced by the immune system to identify and neutralize harmful substances like bacteria and viruses. There are different types, including IgG, IgM, and IgA, each with specific roles in the immune response.

Structur

Immunoglobulins have a Y-shaped structure.

 Each "arm" of the Y contains a variable region that recognizes specific antigens, 

and the stem, 

or Fc region, 

determines the antibody's class and function.

 The basic unit consists of two heavy chains and two light chains connected by disulfide bonds.

There are five main types of immunoglobulins: 

1. IgG (Immunoglobulin G): Predominant in blood and tissues, involved in long-term immunity.

2. IgM (Immunoglobulin M): Found mainly in the bloodstream, the first antibody produced in response to an infection.

3. IgA (Immunoglobulin A): Present in body fluids like saliva and mucous membranes, providing localized defense.

4. IgD (Immunoglobulin D): Found on the surface of B cells, with a role in the activation of B cells.

5. IgE (Immunoglobulin E): Involved in allergic reactions and defense against parasites.

Immunoglobulins exhibit several key properties:

1. **Specificity:** Each immunoglobulin type recognizes and binds to specific antigens.

2. **Diversity:** The immune system can produce a vast array of immunoglobulins, allowing recognition of diverse pathogens.

3. **Memory:** Upon encountering an antigen, the immune system can generate a more rapid and robust response upon subsequent exposure.

4. **Opsonization:** Immunoglobulins can mark pathogens for destruction by phagocytes.

5. **Neutralization:** They can neutralize toxins and prevent pathogens from infecting cells.

6. **Activation of Complement:** Immunoglobulins can trigger the complement system, enhancing the immune response.