370: Immune pathophysiology Flashcards
1st Line of Defense
Physical, Mechanical and Biochemical Barriers
2nd Line of Defense
The inflammatory response
3rd line of Defense
Adaptive immunity
- Cell-mediated immunity
- Humoral immunity
Physical and mechanical barriers such as skin, low temperature, mucus membranes, mechanical cleansing, and cilia.
1st line of Defense
What are the 2 biochemical barriers?
- Epithelial-Derived Chemicals (cathelicidins, defensins, and collectins)
- Bacteria-Derived Chemicals
(Normal bacterial flora)
What are 3 main Epithelial-Derived Chemicals or antimicrobial peptides?
- Cathelicidins
- Defensins
- Collectins
What is the normal bacterial flora in the vagina?
Lactobacillus
What is the normal bacterial flora of the skin?
Pseudomonas aeruginosa
Why does a 3rd Degree burn increase risk for bacterial invasion?
1st line of Defense is removed (skin and anti-microbial)
Jump into the 2nd/inflammatory response
The inflammatory response
2nd Line of Defense
What are the properties of 2nd Line of Defense?
- inflammatory response
- non-specific
- intensity depends on severity of injury
What are the two responses of the 2nd Line of Defense ?
- Vascular Response
2. Cellular Response
What causes the inflammatory response?
- Infection
- mechanical damage
- ischemia
- nutrient deprivation
- temperature extremes
- Radiation
Etc
What are the goals of the inflammatory response?
- Neutralizes/diluted the inflammatory agent
- Remove necrotic material
- Establish environment for healing
What causes Redness in the 2nd Line of Defense?
Hyperaemia from vasodilation
What causes Heat in the 2nd Line of Defense?
Increased metabolism at inflammatory site
What causes Pain & tenderness in the 2nd Line of Defense?
- Change in pH
- Nerve stimulation by chemical mediators
- Increased fluid
What causes Edema in the 2nd Line of Defense?
- Fluid shift
2. Accumulation of fluid exudate
What causes loss of function in the 2nd Line of Defense?
Swelling and pain
Why does ph decrease due to cell damage?
Released potassium
Chemotaxis
Movement of leukocytes in response to chemical signal from area of injury
Margination
Free flowing leukocytes initiate close mechanical contact
Diapedesis
Movement of leukocyte to area of damage
Neutrophils
- First to arrive
- Phagocytosis
- Within 6 hours, only live for 24-48 hrs
When are BANDS released by bone marrow?
- When demand of neutrophils is high
Also known as Left shift
Which leukocytes are involved in the 2nd Line of Defense?
Neutrophils
Eosinophils
Basophils
Monocytes
(Nice Monkeys Eat Bananas)
What is the order of leukocytes from greatest to least quantity?
Neutrophils Lymphocytes Monocytes Eusinophils Basophils
(Nobody Likes Me Emotional Breakdowns)
What is a chemical mediator?
Any messenger that acts on BVs, inflammatory cells or other cells to contribute to any inflammatory response.
Also involved in 2nd Line of Defense
What is Histamine ?
Stored in granules of basophils, last cells, platelets
Mechanism of action of histamine
Causes vasodilation and increased vascular permeability
What are Kinins?
Arise from polypeptides that circulate in the blood in inactive form, Kininogens
What are the anaphylatoxic agents generated from complement pathway activation?
Complement components (C3a, C4a, C5a)
Mechanism of action of Complement components (C3a, C4a, C5a)
- Stimulate histamine release
2. Stimulate chemotaxis
What are Prostaglandins and Leukotrienes?
Produced from arachidonic acid.
Contribute to vasodilation, capillary permeability, pain and fever, leukotriene B4 stimulates chemotaxis
What are cytokines?
Secreted by various cells
Effects vary
The characteristic vascular change at the site of an injury produce:
Increased permeability and leakage
3rd Line of defense
- Adaptive immunity
- Specific response, occurs more slowly than inflammatory response
- Can be induced by vaccination
A molecule that can react with antibodies or receptors on B and T cells
Antigen
An antigen that can trigger an immune response
Immunogenic antigen
The ability of a particular substance to provoke an immune response
Immunogenicity
Protein made specifically against an antigen
Antibody
What are the 2 forms of of adaptive immune system or 3rd line of defense?
- Humoral (antibody-mediated) immunity
2. Cell-mediated immunity
What are the 3 Antibody functions?
Direct: 1. Neutralization 2. Agglutination Indirect 3. Opsonization
Antibody neutralization
Block binding or inactive antigen to receptor on receptor cell
Agglutination
Link microns together
Clumped antigen then filtered out by blood, lymph, or phagocytosis more easily
Opsonization
Marking for ingestion by phagocytes.
Antibodies bind to cell membrane of pathogen.
Antibody titres
Blood test for amoun of antibodies.
Determines if patient is vaccinated and correlated to strength of immune response.
IgG
- Most prevalent
- Most of protective activity against infection
- Crosses the placenta
IgA
- Mostly in secretions
2. Most of protective activity in bonds secretions
IgE
- Most rare
- Mediator of many common allergic responses
- Defends against parasitic infections
IgD
- Not well known
2. Functions as one type of B-cell antigen receptor
IgM
- Largest
2. First antibody produced during the initial, or primary, response to an antigen
Which antibody is most prevalent in the body?
IgG
Which antibody is most rare in the body?
IgE
Which antibody is most protective against infection and crosses the blood brain barrier?
IgG
Which antibody is mediator for allergic responses and defends parasitic infections?
IgE
Latent phase of primary immune response
B-cell differentiation
Which antibody is found in saliva and other body secretions?
IgA