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23 Cards in this Set
- Front
- Back
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Allergies are... |
IgE (antibody) immune responses to harmless antigens |
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The immune response causes the disease: |
Hypersensitivity
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Other hypersensitivities are caused by... |
IgG or by Th1 or Tc activities |
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Autoimmune reactions occur against... |
Self antigens |
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Hypersensitivities |
Type I (anaphylactic)-- < 30mins Type II (cytotoxic)-- 5-12 hours Type III (immune complex)-- 3-8 hours Type IV (cell-mediated or delayed type)--24-48 hours |
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Type I Hypersensitivity: Allergy |
-Immediate hypersensitivity -Reaction in ~ 30 minutes -Inflammation -Symptoms depend on where allergen enters and how severe the immune response is |
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Common allergens |
-Pollens -Pet dander -Dust mite feces -Food antigens |
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Systemic anaphylaxis: |
inflammation throughout circulation ---> death |
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Effects of allergic mediators: |
-Dilated blood vessels -Headache -Constricted bronchioles -Prostaglandin -Excessive mucus, tear formation, glandular secretions -increased peristalisis of intestine; diarrhea, vomiting -increased blood flow -itching |
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Hygiene hypothesis |
-Asthma rates are increasing in the US -Children in day care have lower asthma rates than children kept at home -people from areas with high helminth (worms) infections have low allergy rates ----when those people move to the US, their allergy rates increase |
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Strategies for avoiding allergic symptoms: |
-Monoclonal drugs that inactivate IgE -Corticosteroids keep the plasma cell from synthesizing IgE and inhibit T cells. -Cromolyn acts on the surface of mast cell; no degranulation -Antihistamines, aspirin, epinephrine, theophylline counteract the effects cytokines on targets. |
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Allergy Shots
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Shots induce IgG formation; IgG binds all the allergen so it can't reach IgE on mast cells |
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Type II hypersensitivity |
-IgG/IgM antibodies bind RBC antigens -Complement is activated, lyses RBC -ADCC: macrophages or NK cells bind antibody-coated RBC, kill them |
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Type II Hypersensitivities: |
-Medication allergies -Mismatched blood (transfusion reaction) -Rheumatic fever ---Occurs after infection (Strep throat) -Autoimmune hemolytic anemia --Body attacks own RBCs |
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Type III- Immune complex Disease Type III hypersensitivities |
-Serum sickness: horse anti-snake venom -Lyme arthritis -Systemic lupus erythematosis (SLE): autoimmune disease -Rheumatoid arthritis |
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Type IV: T-Cell Mediated: |
Poison IvyContact Dermatitis : blisters |
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Type IV hypersensitivities |
-TB Skin test -Contact dermatitis to nickel -Other contact dermatitis -Chronis asthma -Autoimmune diabetes (Type I) -Transplant rejection |
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Transplant Rejection |
-Organ grafts: Host T cells kill cells in graft with foreign MHC I and II -Bone Marrow Transplant: mature T cells in graft kill cells in host with foreign MHC I and II |
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Anti-Rejection Drugs |
-Block inflammation --Corticosteroids -Block T cell activity --Cyclosporine A --Monoclonal antibodies |
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Autoimmunity: |
-Often triggered by an infection -MOLECULAR MIMICRY: Immune response to a pathogen antigen generates antibodies and T cells that also bind self antigens -Linked to certain MHC alleles |
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Autoimmune (Type I) Diabetes |
-Virus infection (Coxsackie) -Anti- virus T cells recognize self peptides on islets -Islets destroyed --> insulin dependence |
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Immune Deficiencies |
-Inborn ---Usually a problem in cell development or mutation in gene for an essential protein -Acquired ---Usually due to microbes virulence factors |
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David the "Bubble Boy" |
-Severe combined immunodeficiency disease (SCID) --no T or B cells -Kept alive in sterile environment -Died from cancer caused by EBV in bone marrow transplant from his sister |
