PNP WK3 Flashcards
Immunity, hypersensitivities, autoimmune disease, vaccinations
What is the innate immune defense response?
Prevents entry of damaging substances, non-specific
What are the different barriers of the innate immune system?
- Anatomical: skin and mucous membranes
- Physiological: temperature and pH
- Cellular: Phagocytes, chemical secreter cells, natural killer cells
- Inflammatory
What are interferons?
antivirals that inhibit virus spread, tell NK cells to absorb the infected cell, can also cause apoptosis of infected cell
What is the compliment system?
- cascade of plasma proteins
- activates basophils, mast cells, macrophages/neutrophils = increased inflammation
- promotes opsonization by binding to pathogen
What is the mechanism of action for a phagocytic cell (neutrophil, macrophage and dendrites)?
Absorbs infectious agent, phagolysosome destroys infectious agent
What is the mechanism of action for chemical secreter cells (basophils and mast cells)?
Releases histamine (vasodilator) and heparin (anticoagulant) to increase inflammation
What are eosinphils?
WBC that attach to parasite to destroy through cytotoxic chemicals
What is the adaptive immune defense response?
Specific to harmful substances, selective but slow
What are the four characteristics of adaptive immunity?
- Antigenic specificity
- Diversity
- Immunologic memory
- Self/non-self recognition
What is an antigen?
Molecule that can specifically bind to an antibody, allow body to build defences
What are the classes of antigens and their purposes?
IgA: mucous membrane secretions
IgD: bound to B cell surfaces
IgE: bound to mast cells and basophils
IgG: in humoral immunity
igM: early stages of humoral immunity before IgG is produced
How do antibodies work?
- Opsonization: coat pathogen to enhance phagocytosis
- Complement fixation: coat pathogen and signal blood to destroy it
- Neutralization: coat pathogen to prevent replication
*Circulate in body once created to attack same type of antigens in body
How does the humoral (B cell) response work?
B cells that recognize antigen are selected for cloning, and are either made into plasma cells to produce antibodies, or memory B cells for long term memory
How does the cell-mediated immune response work?
- When a phagocytic cell has a foreign pathogen on its surface (aka an antigen presenting cell), it will go to the lymph node to present to a T cell
- T cell will activate and clone to get rid of infection
What is the difference between Tc (cytotoxic T cell) and Th (helper T cell) cells?
Activated Th cells help activate specific B cells to replicate and become plasma cells
Activated Tc cells leave lymph node to find the infected cells and destroy them and induce lysis
What is a hypersensitive/allergic reaction?
Reactions that are an excessive reaction to an allergen that can cause tissue damage
- Normal immune response is sensitized
- Excessive immune response is hypersensitized
What is IgE mediated/allergic reaction? TYPE I
1st exposure: Antigen presenting cells take allergen to lymph nodes, will produce IgE antibodies
- Th cells will select specific B cell to overproduce IgE
2nd exposure: allergen comes in, binds to mast cell antibodies, causing histamine release
E.G.: Asthma, allergy
What is a cytotoxic reaction? TYPE II
- Antigen attaches to cells which are either intrinsic (self-antigen) or extrinsic (foreign but absorbed on surface)
- Picked up by macro. and dend. cells and act as APCs causing B cell response and antigen production against antigen causing cell to die
E.G. Blood transfusion rejection
What is immune complex reaction? TYPE III
- Freely moving antigens bind to antibodies which get lodged in blood vessels, glomeruli etc. and start the inflammatory process
E.G.: Arthritis, Dermatitis, Vasculitis
What is a delayed reaction? TYPE VI
- Antigen enters skin, is engulfed by APCs and taken to lymph and primes Th cells
- Th induces inflammation (releases cytokines) OR activates Tc cells and destroys APCs/ cell with foreign antigen
What is the pathophysiology of anaphylaxis?
- Histamine released rapidly from mast cells and basophils (degranulation), an onset of vasodilation and severe hypotension, bronchoconstriction and oedema of mucosa
What is the pathophysiology of an autoimmune disease?
- Individuals antibodies against own cells and self tolerance is lost (cannot discern from self and non-self), auto-antibodies trigger inflammation and necrosis
What is the treatment for autoimmune diseases?
NSAIDs used for inflammation and pain
What is the treatment for anaphylaxis?
- Antihistamines for early stages, epinephrine for anaphylactic reaction
What are immunomodulating agents?
Modify body’s immune responsiveness
- Immunostimulants: increase immune responsiveness to fight infection/cancer
- Immunosuppressants: decrease immune responsiveness with hypersensitive/autoimmune reaction
What are examples of immunosuppressants?
- NSAIDs
- Corticosteroids: suppress T-cell activity (Prednisone, Dexamethasone, Cyclosporine)
- Calcineurin inhibitors: Prevent T-cell proliferation by blocking cytokines
Monoclonal antibody therapy: Made by single B-cell clone, make each antibody identical and highly specific
What is immunodeficiency (ID)?
Immune system is unable to prevent or fight infection
Primary ID: mainly affects the immune system (B/T cell deficiencies)
Secondary ID: affects immune function due to effects elsewhere in body (stress, drug intake, nutrition, infection, cancer)
What is the pathophysiology of HIV/AIDS?
Infects dendritic cells, which are taken to lymph nodes which then destroys Th (CD4+ specifically) cells
What is active immunity?
Body is exposed to infectious agent and creates own antibodies, revolves around immunological memory
Natural: infection
Artificial: vaccine
What is passive immunity?
Body receives antibodies against substances, no immunological memory
Natural: breast milk
Artificial: immunoglobin preparation
What is an difference between a vaccines and an antisera/antiserum?
Vaccine: priming the adaptive immune response to the antigens of a particular pathogen
Antisera: Form of passive immunity for immediate short term protection
- Provides humoral products of immunity,
