epitope

Examples of epitope in the following topics:

• Antigenic Determinants and Processing Pathways

  • Antigen epitopes make it possible for the immune system to recognize pathogens.
  • In antibodies, the binding site for an epitope is called a paratope.
  • Although epitopes are usually derived from non-self proteins, sequences derived from the host that can be recognized are also classified as epitopes.
  • Epitopes determine how antigen binding and antigen presentation occur.
  • Most epitopes are conformational.

• Immune Complex Autoimmune Reactions

  • An immune complex is formed from the integral binding of an antibody to a soluble antigen and can function as an epitope.
  • The bound antigen acting as a specific epitope, bound to an antibody is referred to as a singular immune complex .
  • The bound antigen acting as a specific epitope, bound to an antibody is referred to as a singular immune complex.

• Making Memory B Cells

  • To understand the events taking place, it is important to appreciate that the antibody molecules present on a clone (a group of genetically identical cells) of B cells have a unique paratope (the sequence of amino acids that binds to the epitope on an antigen).
  • Some of the resulting paratopes (and the cells elaborating them) have a better affinity for the antigen (actually, the epitope) and are more likely to proliferate than the others.
  • The part of the antigen to which the paratope binds is called an epitope.

• Monoclonal Antibodies

  • Monoclonal antibodies are monospecific antibodies that recognize one specific epitope on a pathogen.
  • Monoclonal antibodies have monovalent affinity in that they bind to the same epitope.

• Extracellular Immune Avoidance

  • Other pathogens invade the body by changing the non-essential epitopes on their surface rapidly while keeping the essential epitopes hidden.

• Enzyme-Linked Immunosorbent Assay (ELISA)

  • The sandwich assay uses two different antibodies that are reactive with different epitopes on the antigen with a concentration that needs to be determined.

• Antigens and Antigen Receptors

  • Any such distinct molecular feature constitutes an epitope.
  • Therefore, most antigens have the potential to be bound by several distinct antibodies, each of which is specific to a particular epitope.
  • Using the "lock and key" metaphor, the antigen itself can be seen as a string of keys - any epitope being a "key" - each of which can match a different lock.
  • Different antibody idiotypes, each having distinctly formed complementarity determining regions, correspond to the various "locks" that can match "the keys" (epitopes) presented on the antigen molecule.

• Antibody Functions

  • Antibodies secreted after binding to one epitope on an antigen may exhibit cross reactivity for the same or similar epitopes on different antigens.
  • Because an epitope corresponds to such a small region (the surface area of about four to six amino acids), it is possible for different macromolecules to exhibit the same molecular identities and orientations over short regions.
  • (b) An antibody may cross-react with different epitopes.

• Antibodies: Classes and Affinity Maturation

  • Humans generate an estimated 10 billion different antibodies, each capable of binding a distinct antigen epitope.
  • A group of antibodies can be called monovalent (or specific) if they have affinity for the same epitope, or for the same antigen (but potentially different epitopes on the molecule), or for the same strain of microorganism (but potentially different antigens on or in it).
  • In contrast, monoclonal antibodies are monovalent for the same epitope.

• MHC Polymorphism and Antigen Binding

  • MHC molecules display a molecular fraction called an epitope and mediate interactions of leukocytes with other leukocytes or body cells.
  • MHC molecules display a molecular fraction called an epitope and mediate interactions of leukocytes with other leukocytes or body cells.