Immunology of Parasites and Hypersens
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- What predominant mechanism by which trypanosomes evade the immune system?
- Waves of antigenic variation conferring resistance to antibody made against previous variants
- What are the characteristics of the for types of hypersensitivity reactions?
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ACID: From I to IV:
Anaphylactic type: type I
Cytotoxic type: type II
Immune complex disease: type III
Delayed hypersensitivity (cell mediated): type IV - What are examples of Type I Hypersensitivty Rxns (6 of them)
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Anaphylaxis
Asthma
Hives(Utricaria)
Local Wheal and Flare
Hay fever(allergic rhinitis)
Food Allergies - What is the mechanism of a Type I Hypersensitivity Rxn?
- Antigen cross links IgE on presented mast cells and basophils triggering release of vasoactive amines (histamine)
- What is the innate immune systems primary mechanism for combatting parasites?
- Macrophages
- How do macrophages combat protozoans?
- Phagocytosis
- How do macrophages combat helminths?
- cytotoxic substances
- What substances tomacrophages rls that mediate inflammation?
- IL- 1, TNF, CSF
- What antibody/cells is associatiated with parasitic worm infections?
- Eosinophils and high levels of IgE lead to dcrs allergies
- In terms of dealing with intracellular infections what Tcell line of defense is best?
- Th1 cells deal better with intracellular parasites by activating the macrophages
- In terms of dealing with extracellular infections what Tcell line of defense is best?
- Th2 with extracellular organisms
- What are the key Th2 Cytokines?
- IL-3, IL-4, IL-5
- What is the role of IL-4 in defense against helminthic infection?
- IL-4 results in class switching to IgE production
- What is the role of IL-5 in defense against helminthic infection?
- IL-5 is a growth factor for eosinophils.
- What are the key Th1 cytokines?
- IL-4, IL-10, IFN-gamma, IL-12 produced by macrophages will up-regulate the IFN-gamma production by the Th1 and NK cells
- What are 2 synonyms for Type I hypersensitivity?
- immediate hypersensitivity or allergy or atopy
- What is characteristic of the early phase of a type I hypersensitivity rxn?
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Rls of Histamine,
cytokines(TNF-gamma, IL-1, IL-4, IL-5, IL-6, IL-13, MIP-1alpha, MIP-1ß, and colony stimulating factors)
Arachidonic acid metabolites include prostaglandins (PGD2), which cause vascular dilatation, and leukotrienes (LTC4, LTD4, LTE4)
Granule proteins: protease and carboxypeptidase - What is characteristic of the late phase of a type I hypersensitivity rxn?
- influx of eosinophils, neutrophils, and Th2 cells is seen and local inflammation
- What is the cause of Type II hypersensitivity?
- Caused by IgM or IgG antibodies directed against cell surface and extracellular matrix antigens: Antibody and complement lead to MAC attack
- What are examples of Type II hypersensitivity?
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Goodpasture's syndrome
Graves' disease
Myasthenia gravis
Insulin-resistant diabetes(Type II)
Erythroblastosis Fetalis - What is the cause of Type III hypersensitivity?
- Ag-Ab-Complement: results from the interaction of preexisting IgG or IgM antibodies with soluble antigen. These give rise to antigen-antibody complexes that are not easily cleared by the immune system and are deposited in tissues and organs
- What are examples of Type III hypersensitivity? (6 of them)
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Systemic lupus erythematosis (SLE)
Serum sickness
immune complex glomerular
nephritis
rheumatoid arthritis
Arthus reaction – localized form of vasculitis in the skin - What are the Types of DTH reactions?
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Insulin-dependent diabetes mellitus (IDDM) aka Type I diabetes.
Multiple sclerosis
Transplant Rejection
Rheumatoid arthritis
Tuberculin type hypersens
Contact dermatitis hypersens(Poison Ivy) - What is the mechanism behind Type IV hypersens?
- Involves the cell mediated branch of the immune system and is characterized by the recruitment of large numbers of nonspecific inflammatory cells. Damage is caused either by triggering delayed-type hypersensitivity (DTH) reactions or by directly killing target cells