What does antibodies do?

Antibodies are essential components of the immune system that play a crucial role in defending the body against foreign invaders and pathogens. Here's an overview of what antibodies do:

1. Antigen Binding: Antibodies are Y-shaped proteins produced by B cells in response to the presence of antigens (foreign substances recognized as non-self by the immune system). Each antibody has specific antigen-binding sites that bind to a particular antigen with high affinity.

2. Neutralization: Antibodies can neutralize toxins and pathogens by binding to them and preventing them from interacting with host cells. This prevents infection or reduces its severity.

3. Opsonization: Antibodies can mark pathogens for destruction by other immune cells. They do this by coating the pathogens with complement proteins, which attracts phagocytic cells like neutrophils and macrophages. This process is known as opsonization.

4. Activation of the Complement System: Antibodies can activate the complement system, a complex network of proteins that aid in the destruction of pathogens. The activation of the complement system can lead to the formation of pores in the pathogen's cell membrane, causing cell lysis (destruction).

5. Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC): Antibodies can also mediate cell-mediated destruction of infected cells or cancer cells. They bind to specific antigens on the surface of these cells and recruit immune cells like natural killer (NK) cells and macrophages, which then release cytotoxic molecules to destroy the target cells.

6. Memory Formation: After an infection, some B cells differentiate into memory B cells. These memory B cells "remember" the specific antigen and can quickly produce antibodies upon subsequent exposure to the same pathogen, providing long-term immunity.

7. Regulation of Immune Responses: Antibodies help regulate the immune response by interacting with regulatory immune cells and molecules. They can dampen excessive immune responses and prevent autoimmune disorders.

Overall, antibodies are critical players in the adaptive immune system's ability to recognize, neutralize, and eliminate invading microorganisms and abnormal cells. They provide protection against infections, contribute to immunological memory, and help maintain immune balance in the body.