opsonization

Examples of opsonization in the following topics:

• The Complement System

  • Activation of the complement leads to robust and efficient proteolytic cascades, which terminate in opsonization and lysis of the pathogen as well as in the generation of the classical inflammatory response through the production of potent proinflammatory molecules.
  • This activity underpins the entire complement system by effectively "tagging" microorganisms as foreign, leading to further complement activation on and around the opsonized surface and terminating in the production of anaphylatoxins and assembly of membrane attack complexes .

• Structure and Function of Antibodies

  • Antibodies contribute to immunity in three ways: preventing pathogens from entering or damaging cells by binding to them (neutralization); stimulating removal of pathogens by macrophages and other cells by coating the pathogen (opsonization); and triggering destruction of pathogens by stimulating other immune responses such as the complement pathway.
  • The complement system starts a long cascade of protein productions that either opsonize a pathogen for phagocytosis or lyse it directly by forming a membrane attack complex.
  • During opsonization, the antibody expresses the tail for an Fc receptor on a macrophage, neutrophil, or natural killer cell.

• The Complement System

  • This process is called opsonization.

• The Complement System

  • The following are the basic functions of the complement: opsonization (enhancing phagocytosis of antigens); chemotaxis (attracting macrophages and neutrophils); cell lysis (rupturing membranes of foreign cells); and clumping (antigen-bearing agents).
  • C3b binds to the surface of pathogens, leading to greater internalization by phagocytic cells by opsonization.

• Antibody Functions

  • Phagocytic enhancement by antibodies is called opsonization.
  • The combination of antibodies and complement enhances opsonization even further, promoting rapid clearing of pathogens.

• Development of the Immune System

  • In neonates, opsonic activity and the ability to activate the complement cascade is very limited.
  • This is due to lower opsonic activity, as well as diminished up-regulation of integrin and selectin receptors, which limit the ability of neutrophils to interact with adhesion molecules in the endothelium.

• Immune Complex Autoimmune Reactions

  • After an antigen-antibody reaction, the immune complexes can be subject to any of a number of responses, including complement deposition, opsonization, phagocytosis, or processing by proteases.

• WBC Function

  • The antibodies bind to pathogens to opsonize (mark) them for phagocytes to engulf, neutralize them, or start a complement cascade in which proteins form a membrane attack complex to lyse the pathogen.

• Types of Adaptive Immunity

  • All antibodies bind to pathogens to opsonize them, which makes it easier for phagocytic cells to bind to and destroy the pathogen.

• Phagocytes

  • The Fc receptor is typically the receptor of use, which binds to antibodies that have opsonized (marked) a pathogen or toxin.
  • Other cells, such as epithelial cells and fibroblasts, may also engage in phagocytosis, but lack receptors to detect opsonized pathogens and are not primarily immune system cells.