HD EX 1 IMMUNE SYSTEM (2) Flashcards
What are the 2 types of immunity?
Non-specific and Specific Immunity.
Non-specific Immunity is…
a wide variety of factors that provide non-selective opposition to the invasion of the body by foreign protein-based substances (antigens). they don’t care what kind of protein it is it’s going to get rid of it.
Antigens
Foreign Proteins.
Examples of Non-Specific Immunity is…
- Inflammation.
- Mechanical Barrier, ie skin
- Enzyme Activity (especially in the GI tract. what you swallow is broken down starting in the mouth).
- Interferons (chemical released in response to ANY viral infection) - Interferons makes it harder for viruses like the cold and flu but they are also what makes you feel crummy and nauseous.
- pH (acid and alkaline) - GI system, the stomach has a pH of 3 that not many protein substances can last long at that level.
Specific Immunity responds to…
a specific antigen (foreign protein). Zeroes in on 1 foreign antigen.
There are 2 types of Specific Immune Actions.
- Cell-Mediated Immunity
2. Immunoglobulins Humoral Immunity
Cell-Mediated Immunity
Does not involve antibodies.
Lymph nodes and Lymphoid Tissue -> T. Lymphocytes -> Thymus Gland -> Activated Lymphocytes ->
1. Cytotoxic T Cells (killer cells): by secreting substances, lymphotoxins (knocks out) and lymphokines (attracts and gets out of body).
2. Helper T Cells (t4) stays active indefinitely and recognizes foreign protein if it comes back and will get killer cells.
3. Suppressor T Cells (t8) call off killer t cells when done to stop damage.
Immunoglobulins Humoral Immunity
Involves Antibodies.
Lymph nodes and Lymphoid Tissue -> B. Lymphocytes ->
1. Plasma Cells.
2. Memory Cells.
Antibodies act on antigen usually with killer t’s.
B. Lymphocytes, Plasma Cells will become 1 of 5 types of antibodies…
- IgG - most abundant; crosses placenta
- IgA - in plasma and mucus membrane
- IgD - not sure what it does, tends to form with IgA
- IgE - increased with allergy
- IgM - largest physically
Antigen-Antibody Complex Action:
Antigen is rendered harmless by one of a combination of the following…
- Precipitation - antigen becomes solid so can’t easily move into cell.
- Agglutination - the precipitate start to clump together.
- Opsonization - Usually lymphokine (marks it?)
- Neutralization - If antigen is bacteria, the antibody will figure out the chemical structure the bacteria is producing and produce a neutralizing substance.
Complement
A series of protein enzymes that attach to antigen-antibody complexes involving IgG and IgM. IMMUNE COMPLEXES MAY DAMAGE HOST CELLS AS WELL AS ANTIGEN
2 ways to acquire immunity without getting sick:
- active immunity
2. passive immunity
Active Immunity
Person forms antibodies by:
- Vaccine (deactivated bacteria or virus). Triggers immune system and create formations of t helper and memory cells. Ex: polio vaccine.
- Toxoid (chemically altered toxin). Ex: tetanus toxoid.
- Long-lived Immunity (requires time) lasts 10-15 years but takes 10-14 days to acquire the immunity.
Passive Immunity
Preformed antibodies received (usually in immune horse serum). Cultavated antibodies. Ex: stepped on a nail, need protection right away. Inject horse serum with T. lymph and B. Lymph.
Short lived. Lasts 10-14 days but serum is recognized as antigen so body will get rid of it as well.
Hypersensitivity
Immune response to antigen that is usually not harmful and response may cause harm.
4 types of hypersensitivity:
- Allergy
- Cytotoxic
- Immune Complex Mediated
- Cell Mediated
Hypersensitivity: Allergy
- Increased amount of IgE.
- IgE and antigen attach to mast cell, forming antigen-antibody complex.
- Mast cell releases histamine and other inflammatory mediators.
- Local - Asthma (airways swell up, histamine in airway, make smooth muscle constrict making less room for air), hay fever, hives (urticaria), GI food allergy.
- Generalized (throughout the body) - Anaphylaxis (systemic release of histamine causes low blood pressure and swollen airways and is life threatening) Each time you are exposed to an allergen it gets worse each time.
Hypersensitivity: Cytotoxic
- Complement attaches to IgG or IgM antigen-antibody complex (now called an immune complex).
- Individual cells are lysed (most commonly RBCs)
- Examples: Rh disease (Erythroblastosis Fetalis), Transfusion reactions (may also cause anaphylaxis)
Hypersensitivity: Immune Complex Mediated
- Immune complexes, ie IgG or IgM with complement activated, cause damage to large area of host tissue. Large surface area and complete organ systems.
- Examples: Glomerulonephritis (damage to filter part of kidney), Rheumatic Fever (reaction to strep or staph infection)
Hypersensitivity: Cell Mediated
- T Lymphocytes (killer t’s) attack harmless antigenic substances.
- May take 1-2 days to develop (quick)
- Examples: transplant rejection, TB skin test
Immune Deficiencies, 2 types with examples
Congenital:
-Agammaglobinemia (born without ability to make B. Lymphocytes and in severe versions T. Lymphocytes. Raised in sterile environment like bubble boy or will need bone marrow transplant.
Acquired:
- Malignancies (cancer) of the bone marrow and lymphatic system (trouble with immunity)
- Chemotherapy (damages marrow cells not just cancer cells)
- Steroids (quells inflammation but also quells immune system)
- AIDS
AIDS
Acquired Immune Deficiency Syndrome.
AID etiology
HIV - Human Immunodeficiency Virus
HIV can be found in
ALL BODY FLUIDS of infected persons but most easily transmitted by:
- infected blood, semen, and vaginal secretions. (attacks t4 lymphocytes - has to get to unaffected blood)
- unprotected exposure to body fluids puts everyone at risk, eg health care workers. (friction causes erosion and exposure through mucus membranes during unprotected sex).
High risk practices:
IV drug abuse
Unprotected sex (includes anal sex)
