This process of antibody production is crucial for the adaptive immune response, as it enables the immune system to recognize and respond specifically to a wide range of pathogens and antigens.
Antigen recognition: When a foreign substance enters the body, specialized cells of the immune system, such as B lymphocytes (B cells), recognize the antigens present on the surface of the invader. Antigens are molecules that can trigger an immune response.
Activation of B cells: Once B cells recognize the antigen, they undergo a process called activation. This typically occurs when the antigen binds to specific receptors on the surface of the B cell. The activated B cells then undergo clonal expansion, meaning they multiply rapidly to produce a large number of identical B cells.
Differentiation: Some of the activated B cells differentiate into plasma cells. Plasma cells are antibody factories and are responsible for producing and secreting large amounts of antibodies. Other activated B cells differentiate into memory B cells, which play a role in long-term immunity. Memory B cells “remember” the antigen encountered, allowing for a faster and more robust response upon subsequent exposures to the same antigen.
Antibody production: Plasma cells produce and release antibodies into the bloodstream and other bodily fluids. Antibodies, also known as immunoglobulins (Ig), are Y-shaped proteins that bind to specific antigens. The binding of antibodies to antigens can help neutralize pathogens, mark them for destruction by other immune cells, or activate other components of the immune system.
Antibody functions: Antibodies perform various functions to combat foreign substances. These functions include:
Neutralization: Antibodies can bind to pathogens, preventing them from infecting cells and neutralizing their harmful effects.
Opsonization: Antibodies can mark pathogens for destruction by phagocytic cells, such as macrophages, which engulf and destroy the tagged invaders.
Activation of the complement system: Antibodies can trigger the complement system, a series of proteins that work together to destroy pathogens by forming pores in their membranes or tagging them for phagocytosis.
Antibody-dependent cellular cytotoxicity (ADCC): Antibodies can bind to infected or abnormal cells, marking them for destruction by immune cells like natural killer (NK) cells.