Immunology & Serology

• Immunology


  The study of the immune system and its responses to the invading pathogens
• Immune system


  The collection of cells, tissues and molecules that mediate resistance to infections
• Immune response


  The coordinated reaction of these cells and molecules to the infectious molecules
• Immunity


  State of protection against foreign organisms or substances (antigens) (innate & adaptive)
• Serology


  The science of antigen-antibody reactions of the body using a serum specimen
• Purpose of serology


  To diagnose infectious diseases by observing the presence of an immune antibody in the patient, resulted from infection or entry by the pathogen into the body
• Applications of immunology


  • Diagnosis of diseases
  • Understanding of diseases process
  • Prevention and treatment of diseases
  • Blood transfusion serology
  • Tissue typing and histocompatibility testing
  • Forensic medicine
• Innate immunity


  First & second line of defense; include barriers, phagocytic cells & molecules
• Adaptive immunity


  More effective & defense against infections
• Types of immunity


  • Innate immunity
  • Adaptive immunity
• Components of innate immunity

  • Physical & chemical barriers
  • Blood proteins
  • Cells
• Components of adaptive immunity

  • Cutaneous and mucosal immune systems; secreted antibodies
  • Antibodies
  • Lymphocytes
• Innate immune system reacts to a given stimulus with a consistent intensity, regardless of how many times it has been exposed to that stimulus
• Adaptive immune system can adapt and modify its response after each exposure to a given stimulus
• Antigen


  Any agent that binds to components of the immune response: lymphocytes and their receptors (antibodies and the T cell receptor)
• Immunogen


  Any substance that induces a specific immune response mediated by either T cell or B cell or both
• Criteria for immunogenicity


  • Foreignness
  • High molecular weight
  • Chemical complexity
  • Dosage and route of administration
  • Genetic constitution of the host
• Classification of antigens


  • According to chemical nature: Proteins, Polysaccharides, Lipids, Nucleic acids
  • On the basis of mode of action: Thymus dependent antigen, Thymus independent antigen
  • On the basis of epitope or antigenic determinant: Unideterminant univalent, Unideterminant multivalent, Multideterminant multivalent
  • Superantigens
• Antigenic determinant or epitope


  Specific portion of macromolecule antigen which antibody or T cells bind
• Types of epitopes


  • Linear epitope
  • Conformational epitope
• Hapten


  Low molecular weight compounds that are antigenic but not immunogenic by themselves
• Mitogen


  A small bioactive protein or peptide that induces a cell to begin cell division, or enhances the rate of division (mitosis)
• Adjuvant


  Substances that enhance the immune response to an antigen
• Immunology is the branch of biomedical science that deals with the response of an organism to antigenic challenge and its recognition of what is self and what is not
• In immunology, an antigen is a molecule capable of inducing an immune response on the part of the host organism, though sometimes antigens can be part of the host itself