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What are the body's 3 lines of defense?
1) Innate/non-specific; anatomical and biochemical barriers
2) Non-specific/immediate: inflammatory response
3) Specific/slow: immune response
What is an antigen?
A substance that produces a specific immune response. Typically a pathogen and a protein.
What is a pathogen?
Any virus, microorganism, or other substance causing (infectious) disease.
What are the 2 forms of immunity?
- Innate immunity: genetically determined, non-specific defense mechanisms
- Acquired immunity: gained after birth, specific protection against specific antigens
What are some examples of innate immunity?
Physical barriers (skin), normal bacterial flora, tears, mucous, coughing, urination, vomiting.
What are some innate, nonspecific resistance factors?
- Fever: inhibits some pathogens; speeds up body's metabolism
- Interferons: interfers with viral replication inside the cell
- Complement: an opsonin; makes phagocytosis easier
- Lysozyme: enzyme that can destroy some foreign organisms
- Lactoferrin: binds/removes iron
- Alpha anti trypsin: inhibits bacterial enzymes
Acquired immunity can either be ____ or ____, which can then be either ____ or ____.
Passive or active
Natural or induced
What is passively acquired immunity?
Produced by transfer of antibodies from another person; temporary.
Natural: Colostrum, protects infants until of age
Induced: Serum, snake anti-venom, tetanus antitoxin
What is actively acquired immunity?
Produced by antibodies that develop in response to antigens; permanent.
What is the difference between first and sceond exposure?
The primary response takes about two weeks and IdG levels do not remain elevated. The secondary response is characterized by a very rapid increase in IgG that remains elevated for an extended period.
What are the 4 goals of a good immune system?
- Specificity: targets particular antigen
- Versatility: differentiates between antigens
- Memory: second exposure is stronger and lasts longer
- Tolerance: does not respond to "self" antigens
What are the 5 different cells of the immune system?
- Monocytes (macrophages)
Where are lymphocytes formed and what are the two different cell lines?
They are formed in the bone marrow.
- B Lymphocytes: B cells, humoral (antibody-mediated) immunity
- T Lynphocytes: T cells, cell-mediated immunity
How to B cells demonstrate humoral immunity?
When B cells encounter antigens, they are stimulated to become mature plasma cells that secrete specific antibodies.
What 2 cell lines result from activated B cells?
- Memory B cells
- Plasma cells: produce/secrete immunoglobulins (antibodies)
Describe the structure of an antibody.
Two polypeptide (protein) chains in the shape of a 'Y'
What are the 5 classes of immunoglobulins?
What is IgG?
Accounts for 80% of immunoglobulins, responsible for most antibody functions.
What is IgA?
The predominant antibody in normal body secretions.
What is IgM?
First antibody secreted after the arrival of an antigen.
What is IgE?
IgE is predominant is allergiv reactions.
What is IgD?
Plays a rold in activated B cells to produce antibodies.
What are the 4 funtcions of antibodies?
- Neutralize bacterial toxins
- Neutralize viruses
- Opsonize bacteria
- Activate complements of the inflammatory response
What percentage of T cells account for all lymphocytes?
How to T cells demonstrate cell-mediated immunity?
T cells recognize specific antigens, which they attack directly. (antigen-specific)