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28 Cards in this Set
- Front
- Back
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What is an antigen (Ag)?
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An antigen (Ag) is usually a protein or polysaccharide that is recognized by the body as a foreign matter.
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What is an epitope?
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An epitope is a part of an Ag that actually binds to an Ab.
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What is the function of B cells?
What s the specialized, secreting progeny cell called? |
B cells produce antibodies (Abs). The specialized, secreting progeny cell is a plasma cell.
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How much time is required to produce Abs?
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7-10 days are required to produce Abs.
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What other cell type, besides plasma results from B cell proliferation? What is it's function?
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Memory B cells also result from B cell proliferation. Their function is to provide a quick response to a future Ag exposure by producing Abs against that Ag.
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What does a Th cell cause to happen to many immune cells?
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The Th cell causes the proliferation of many immune cells.
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Where do B and T cells mature?
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B cells mature in the bone marrow. While T cells start in the bone marrow, they mature in the thymus.
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What three cell types are required for an acquired immune response, and what cells secrete them?
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The 3 cells types req for an acquired immune response are the antigen presenting cell (APC), the T helper (Th), and a B or T cell that is stimulated to proliferate.
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What two cytokines are required for an acquired immune response, and what cells secrete them?
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The cytokines IL1 (interleukin 1) and IL2 (interleukin 2) are required for an acquired immune response. IL1 is secreted by the APC and IL2 is secreted by the Th cell.
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What cells are not stimulated when a T-independent Ag (such as a polysaccharide) is detected by the immune system?
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Th cells are not stimulated when a T-independent antigen (such as a polysaccharide) is detected by the immune system, and thus no memory cells are formed.
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What is the purpose of a plasma cell?
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The purpose of a plasma cell is to produce Abs that recognize and bind to specific Ags.
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How many Ag binding sites does IgG have? IgM? Secretory IgA (sIgA)?
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IgG has 2; IgM has 10; sIgA has 4
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Which Ab class has the longest half-life?
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IgG has the longest half-life: 21 days
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Which Ab classes opsonize Ags?
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IgG and IgM opsonize Ags
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How do Abs fix complement?
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Abs IgG and IgM fix complement; when they bind to a pathogen, a C3 binding site is exposed to so that complement begins its cascade of protein binding.
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`Why do we resist a second round of infection with the 3d measles virus?
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We resist a second round of infection because in a second infection, the virions are destroyed by B cells and T cells that recognize the viruse's Ags before the disease becomes symptomatic.
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What is the difference between active and passive immunity?
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Active immunity induces the immune sys into a protective state by introducing a weakened or killed microbe before exposure to the virulent microbes occurs. Passive immunity introduces specific antibodies from one host to another recently exposed individual. No long-term immunity occurs because the individual's immune sys is not stimulated, and the Abs are slowly degraded.
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Small Ab:Ag compleses can give rise to what types of disease?
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Small Ab:Ag complexes can give rise to arthritis, vasculitis, glomerulonephritis, and other immune complex diseases.
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What is an allergen?
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An allergen is a substance that provokes an allergic response by inducing IgE production.
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Why doesn't a person have an allergic response during the first exposure to an allergen?
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A person doesn't have an allergic response during the first exposure to an allergen because the first exposure results in the production of IgM. In subsequent exposures, the expression of Ab classes may switch to the production of IgE, which then binds to mast cells and basophils to make them sensitized.
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What does humoral immunity refer to?
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Humoral immunity refers to Abs.
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Why is delayed-type hypersenstivity reaction hard to the touch?
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A delayed-type hypersensitivity reaction is hard to the touch because it is tightly packed with immune cells.
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Briefly describe the mechanisms for the 4 types of hypersensitivity reactions:
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4 types of hypersensitivity reactions:
- Type1: Allergens bnd to IgE Ab on mast cells and basophils that release histamine. -Type2: Abs in the host bind to host Ags, fix complement, and opsonize the Ags so that complement and phagocytes destroy the Ags. -Type3: Small complexes of Ab:Ag form and are filtered out in the kidney or stick to host tissues where phagocytic cells attack the whole complex tissue areas. -Type4: Tcells, especially Tc cells, are recruited to the site by foreign Ags. The Tc cells release toxic chemicals in the area. |
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Define: Bruton's disease
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Pt makes no B cells
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Def: DiGeorge syndrome:
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Pt makes no T cells, d/t a failed thymus.
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Def: Severe combined immunodeficiency:
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The stem cells in the bone marrow do not produce B or T cells.
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Def: Acquired immunodeficiency:
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The virus kills the Th cells that control nearly all other immune responses.
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5 auto immune diseases:
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1. RA, Rhuematoid arthritis
2. IDDM, Insulen depndent diabetes mellitus 3. Systemic lupus erythematosus 4. MS, Multiple sclerosis 5. MG, Myasthenia gravis |
