M1

• Immunology is the study of immunity, which is the resistance to infectious diseases.
• Immunity is the major function of the Immune System
• The Immune System is structured to recognize, respond to, and destroy invading microorganisms like bacteria, viruses, fungi, and parasites
• Survivors of common infectious diseases in the past rarely contracted the disease again, rooted to the development of the science of immunology
• Immunology consists of:

  • The study of molecules, cells, organs, and systems responsible for recognizing and disposing of foreign material
  • How body components respond and interact
  • Desirable and undesirable consequences of immune interactions
  • Ways in which the immune system can be manipulated to protect against or treat disease
• Significant milestones in immunology include:

  • Edward Jenner's smallpox vaccination in 1798
  • Louis Pasteur's live, attenuated chicken cholera and anthrax vaccines in 1880-1881
  • Elie Metchnikoff's cellular theory of immunity through phagocytosis in 1883-1905
  • Robert Koch's demonstration of cutaneous hypersensitivity in 1891
  • Jules Bordet's discovery of complement in 1894
  • Paul Ehrlich's antibody formation theory in 1900
  • Charles Richet and Paul Portier's discovery of immediate-hypersensitivity and anaphylaxis in 1902
• • Adaptive immunity: characterized by specificity for each pathogen and ability to remember prior exposure
  • Adjuvant: substance that enhances and potentiates the immune response
  • Adoptive immunity: results from transferring immune cells from an immunized host to a nonimmune individual
  • Affinity: initial force of attraction between an antibody and antigen
• Terms in immunology:

  • Accelerated rejection: occurs within 1 to 5 days after second exposure to tissue antigens
  • Acquired immunodeficiency syndrome (AIDS): caused by HIV affecting the immune system
  • Active immunity: results from natural exposure to an infectious agent or vaccine
  • Acute graft-versus-host disease (GVHD): occurs shortly after immunocompetent cells are transplanted, characterized by skin rashes, diarrhea, and increased susceptibility to infection
  • Acute rejection (AR): occurs days to weeks after transplantation due to cellular mechanisms and antibody formation
• Agglutination inhibition:

  • Based on competition between antigen-coated particles and soluble patient antigens for a limited number of antibody-combining sites
  • Lack of agglutination is a positive test result
• Agglutinin:

  • An antibody that causes clumping or agglutination of the cells that triggered its formation
• Allergen:

  • An antigen that triggers a type I hypersensitivity response (i.e., an allergy)
• Alloantigen:

  • An antigen found in another member of the host’s species and capable of eliciting an immune response in the host
• Allograft:

  • Tissue transferred from an individual of one species into another individual of the same species
• Allotype:

  • A minor variation in amino acid sequence in a particular class of immunoglobulin molecule that is inherited in Mendelian fashion
• Alternative pathway:

  • Means of activating complement proteins without an antigen-antibody combination
  • Triggered by constituents of microorganisms
• Amplicon:

  • A copy of a select portion of DNA obtained by the polymerase chain reaction (PCR)
• Amplification:

  • Copying of nucleic acids to increase the amount available for testing
• Analyte:

  • The substance being measured in an immunoassay
• Analytic sensitivity:

  • The lowest measurable amount of an analyte
• Analytic specificity:

  • An assay’s ability to generate a negative result when the analyte is not present
• Anaphylatoxin:

  • A small peptide formed during complement activation that causes increased vascular permeability, contraction of smooth muscle, and release of histamine from basophils and mast cells
• Anaphylaxis:

  • A life-threatening response to an allergen characterized by the systemic release of histamine
• Anergy:

  • A state of immune unresponsiveness to a specific antigen
• Antagonism:

  • When the action of one cytokine counteracts the activity of another cytokine
• Antibodies:

  • Glycoproteins produced by B lymphocytes and plasma cells in response to foreign substance exposure
  • Also known as immunoglobulins
• Antibody-dependent cell cytotoxicity (ADCC):

  • The process of destroying antibody-coated target cells by natural killer cells, monocytes, macrophages, and neutrophils, all of which have specific receptors for an antibody
• Antibody-drug conjugates:

  • Antibody attached to toxins or radioisotopes to help specifically destroy cancer cells
• Antigen:

  • Macromolecule capable of eliciting formation of immunoglobulins (antibodies) or sensitized cells in an immunocompetent host
• Antigen-dependent phase:

  • The final phase of B-cell development, which occurs when a B cell is stimulated by an antigen and undergoes transformation to a blast stage, resulting in the formation of memory cells and antibody-secreting plasma cells
• Antigen-independent phase:

  • The first phase of B-cell development in the bone marrow, resulting in mature B cells that have not yet been exposed to antigen
• Antigen presentation:

  • The process by which degraded peptides within cells are transported to the plasma membrane with MHC molecules so T cells can then recognize them
• Antitoxin:

  • Antibody used in passive immunization for the purpose of neutralizing a bacterial toxin
• Apoptosis:

  • Programmed cell death
• Arthus reaction:

  • A type III hypersensitivity skin reaction that occurs when an animal has a large amount of circulating antibody and is exposed to the antigen intradermally, resulting in localized deposition of immune complexes
• Atopy:

  • An inherited tendency to respond to naturally occurring allergens, resulting in the continual production of IgE
• Attenuation:

  • Process of producing nonpathogenic bacteria or viruses for use in vaccines
  • Organisms weakened by treatment with a chemical, exposure to elevated or cold temperatures, or repeated in vitro passage in cell culture
• Autoantibody:

  • An antibody produced against an antigen found on an individual’s own cells, tissues, or organs
• Autoantigen:

  • An antigen that belongs to the host and is not capable of eliciting an immune response under normal circumstances
• Autograft:

  • Tissues removed from one area of an individual’s body and reintroduced in another area of the same individual
• Autoimmune disease:

  • Condition in which damage to body organs results from the presence of autoantibodies or autoreactive cells