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50 Cards in this Set
- Front
- Back
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Innate Immunity |
-Present at birth -NOT specific -Macrophages, polymorphonuclear leukocytes
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Adaptive Immunity |
-Memory and exquisite specificity -T cells and B cells -Occurs after a person has been exposed to an antigen and as a result, the immune system becomes sensitized to the antigen |
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Neutrophils |
-50-70% of leukocytes -First cells to arrive at the site of injury -Main function is to phagocytize microbes -Granules contain various enzymes that digest biological materials and generate free radicals that destroy bacteria cell membranes |
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Basophils |
-0.5-1.0% of leukocytes -Function is similar to mast cells -Contain granules that contain histamine which is released once an allergen binds to an IgE antibody -Contain chemical mediators (prostaglandins, leukotrines) -S/s of allergic reaction: bronchoconstriction, increased mucous production, pruritus, vasopermeability, and vasodilation |
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Eosinophils |
-3-5% of leukocytes -Contain cytosolic granules of toxic enzymes and a type of protein that are particularly effective against parasites -Hallmark of allergic reactions |
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Macrophage |
-Have receptors for foreign antigen and can recognize CHO units foreign to vertabrates -Have receptors for complement components and for the Fc receptor on antibodies -Lysosomes are filled with digestive enzymes, superoxid, allowing Macrophages to kill on the spot -Play a role in stimulating adaptive immunity via antigen presentation to T helper cells and cytokine production |
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T lymphocytes |
-Dependent on the thymus gland for maturation. Precursor T cells migrate from the bone marrow to the thymus gland and undergo cell division and maturation -Antisocial- don't want any cell that doesn't belong to host |
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T helper cells |
-Aka CD4 cells -Contain HLA type II MHC glycoproteins -Facilitate or amplify cytotoxic T cell responses or B cell responses via the release of specific cytokines |
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Cytotoxic T cells |
-Aka CD8 cells -Contain HLA type I MHC glycoproteins -These are the cells that kill target cells expressing specific foreign antigens associated with self-molecules -Critical in recovery from viruses and some ypes of bacteria that invade and multiply INSIDE the cells |
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3 pools of neutrophils |
-Bone marrow pool -Circulating pool -Marginal pool: these are the neutrophils adhering to the vascular wall |
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"Segs" |
-Segmented neutrophils are the mature form of neutrophils. |
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"Bands" |
-The more immature form of neutrophils that are often elevate during times of infection |
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"Left- shift" |
-Indicates a progressive increase in neutrophil count coupled with an increase in the immature form (bands) |
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Cell-Mediated Immunity |
-Involves the T cells -Recognizes antigens when presented on HLA receptors on self molecules (MHC) |
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Humoral Immunity |
-Involves the B cells -Think antibodies and PREVENTION -Can recognize a foreign antigen in circulation. The antigen does NOT have to be presented bound to a self-molecule |
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Major Histocompatibility Complex (MHC) |
-All nucleated cells have histocompatibility molecules that identify the cell as belonging to the host -Called Human Leukocyte Antigens (HLA) -The MHC is a region on chromosome 6 where the genes are located that encode for these specific membrane MHC glycoproteins -Many alleles within the population |
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Class I |
-MHC complex -HLA-A, B, & C -Single glycoprotein -Function is to bind antigenic peptides derived from intracellular foreign antigens (viruses) -CD8 T cells bind to class I -Involved in transplant rejections |
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Class II |
-MHC complex -HLA-DR, HLA-DQ, & HLA-DP -Two glycoprotein chains, one alpha and one beta -Found on immune cells known as APCs -CD4 T cells bind to class II |
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Allele |
-A variation to a certain gene -The reason why people are so immunologically different |
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Normal CD4 Count |
600-1200 cell/mm3 |
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< 200 CD4 |
-Indicates the conversion of HIV into AIDS |
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Immunoglobulins |
-aka antibodies, are glycoprotein molecules produced by plasma cells. They act as a critical part of the immune system by specifically recognizing and binding to particular antigens, such as bacteria or viruses and aiding in their destruction |
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IgG |
-Represents the largest portion (75-80%) -Directed against common infectious agents like viruses, bacteria, and toxins -Only immunoglobulin that crosses the placental barrier -Activates complement and binds to macrophages |
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Igm |
-5-10% -Part of the primary immune respone -Activates complement -Forms the natural antibodies for AB blood antigens |
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IgA |
-15% -Major function in mucosal immunity |
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IgE |
-0.00004% -Binds to mast cells and basophils -Associated with ALLERGIC and hypersensitivity reactions -protective against parasites |
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IgD |
-0.2% -Found as a surface marker on B cells, usually in association with IgM |
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Purpose of immunoglobulin therapy? |
Agglutination Precipitation Neutralization Complement |
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Agglutination |
The binding sites of antibodies allow them to trap antigens or clump antigens together thus facilitating phagocytosis by the scavenger cells |
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Precipitation |
The antigen-antibody complex becomes so large that it becomes insoluble and precipitates into particles. The particles are phagocytized by macrophages. |
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Neutralization |
The process of coating toxic antigenic sites with antibodies so they can easily be ingested by scavenger cells |
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Complement |
Results in opsonization of the antigen. |
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Opsonization |
The process of coating an antigen with an antibody/complement to facilitate phagocytosis by scavenger cells |
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Purpose of the complement system |
-1)Enhances the immune system -2) Increases vascular permeability and vasodilation by the release of histamine (allergic response) -3) Form a membrane attack complex |
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Definition of complement system |
-A complex system of proteolytic, regulatory, and inflammatory proteins that function to assist in the elimination of foreign microbes in both innate and humor immunity |
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Anaphylatoxins |
-Are C3a, C3b, and C5a. -They increase vascular permeability and cause vasodilation by binding to mast cells, which in turn release histamine. C5a also activates the lipoxoygenase pathway of arachidonic acid metabolism which results in increased release of inflammatory products |
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Role of Antibodies |
-Prevention!!!! -Able to bind to circulating FREE antigens |
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Role of T lymphocytes |
-RECOVERY from current infection -Able to bind to APCs and kill them (unable to bind to free circulating antigens) |
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TXA2 |
-Increases platelet aggregation -Causes vasoconstriction -Synthesized by plasma cells |
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PGI2 |
-Causes vasodilation -Inhibits platelet aggregation -Endothelial cells lining the blood vessels have prostacyclin synthase |
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Fatty Acid precursors and their PGs & LTs |
Linoleic: PG1, LT 3 Arachidonic: PG2, LT4 EPA (derived from Alpha-linolenic): PG3, LT5 |
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Effect of ASA on immune system |
-inhibits cyclooxygenase pathway, therefore decreasing the production of TXA2 and decreasing thrombus formation |
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Effect of steroids on the immune system |
-Inhibit phospholipase A2, which prevents both cyclooxygenase pathway and 5-lipoxygenase pathways -Most effective drug on allergic responses because it inhibits the initial pathway, thus preventing further response from the immune system |
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Cyclooxygenase Pathway |
-Catalyzes the conversion of arachidonic acid to an endoperoxide called PG2-> PGH2 -> biologically active end products: TXA2, PG2, PGF2a, PGE2, and PGD2 |
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5-lipoxygenase pathway |
-Converts arachidonic acid to hydroperoxyeicosatetrenoic acid (HPETE). This is eather reduced to 5-HETE and chemotactic to neutrophils, or it is converted to a family of compounds called leukotrines
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Leukotrienes |
-Formed in leukocytes, mast cells, platelets, and macrophages. -Slow reacting substances of anaphylaxis |
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Interleukin-2 |
-Involved in the proliferation and differentiation of lymphocytes -Particularly potent in stimulating cytotoxic T cells -It is a T cell growth factor |
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Function of cytokines |
-Are polypeptide products of many cells types that function as mediators of inflammation and immune response |
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Interleukin-1 |
-Activates T helper cells, induces various mediators of inflammation like the prostaglandins, and mobilizes neutrophils to the site of injury |
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Interleukin-5 |
-Activates eosinophils (boo) |
