1 Flashcards
What is immunity?
State of increase resistance to disease
Immunity is the sum of all naturally occurring defense mechanisms to protect humans from infectious agents and their products.
What are the two main types of immunity?
- Innate immunity (Natural or Non-Specific)
- Acquired immunity (Adaptive or Specific)
What are the characteristics of innate immunity?
- Pre-exist
- Non adaptive
- Non specific
- No Memory
What are the components of innate immunity?
- Mechanical Barriers
- Humoral (Chemical) Barriers
- Cellular Barriers
List examples of mechanical barriers in innate immunity.
- Intact skin & Mucous membrane
- Mucous
- Beating cilia of epithelium
- Flushing action of saliva, tears, urine
- Vomiting, peristalsis, diarrhea
What are humoral barriers in innate immunity?
- Tears (Lysozyme)
- Saliva (Enzymes)
- Skin (Sebaceous secretions)
- Gastric acid
- Bile acids
- Trypsin
- Lactoferrin, Transferrin
- Complement components
- Interferons
What is the function of interferons?
- Induce an anti-viral state in uninfected cells
- Enhance T-cell activity
- Activate macrophages
- Increase cytotoxic action of NK cells
- Enhance expression of MHC molecules
What are the types of interferons?
- Alpha-IFN (Secreted by Macrophages)
- Beta-IFN (Secreted by Fibroblasts)
- Gamma-IFN (Secreted by T-lymphocytes)
What defines natural killer (NK) cells?
Large granular lymphocytes that are innate cytotoxic lymphocytes
What factors contribute to innate immunity?
- Inflammatory process
- Body temperature
- Hormonal balance
- Age
What are the two interrelated mechanisms of acquired (adaptive) immunity?
- Humoral Immunity (B-cells)
- Cellular Immunity (T-cells)
What are the characteristics of adaptive immunity?
- Ability to distinguish self from foreign
- Antigenic specificity
- Immunologic memory
- Diversity
Define the primary immune response.
- There is lag phase
- IgM class
- Low affinity Ab
- Ab titer is low
Define the secondary immune response.
- No lag phase
- IgG class
- High affinity Ab
- Ab titer is high
What distinguishes active immunity from passive immunity?
- Active immunity is induced after contact with foreign antigen
- Passive immunity is based on antibodies preformed in another host
What are the two types of active acquired immunity?
- Natural active acquired immunity
- Artificial active acquired immunity
What are the two types of passive acquired immunity?
- Naturally passive acquired immunity
- Artificially passive acquired immunity
What is the difference between antigens and immunogens?
- Antigens react with antibodies
- Immunogens induce an immune response
List the criteria of immunogenicity.
- Foreignness
- Chemical structure
- Molecular weight
- Dose, Route of Ag administration
- Genetic constituents of host
- Antigenic determinants (Epitopes)
What is an epitope?
The portion of antigen with which antibodies and T-cell receptors react
What is the function of adjuvants?
Enhance the immune response to an immunogen
What is a hapten?
A small organic molecule that is non-antigenic and non-immunogenic
What is the significance of the valence of an antigen?
It is equal to the total number of epitopes that the antigen possesses
True or False: The innate immune system is enhanced by repeated exposure.
False
