Term
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Definition
Surface barriers (skin, mucous membranes)
Internal defenses (phagocytes, NK cells, inflammation, antimicrobial proteins, fever) |
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Term
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Definition
Humoral immunity (B cells)
Cellular immunity (T cells) |
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Term
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Definition
| develop from monocytes to become the chief phagocytic cells. Free macrophages go everywhere, fixed macrophages are permanent residents of some organs |
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Term
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Definition
| become phagocytic when they encounter infectionus material in tissues |
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Term
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Definition
| kills anything that comes close to it |
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Term
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Definition
| lysosomes will go to the surface and degranulate (discharges enzymes into the tissue & when the enzymes get out, the cause a reaction to burst |
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Term
| Neutrophil Respiratory burst |
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Definition
| the neutrophil will rapidly absorb oxygen and reduce it (add electron) creates super oxide anion which reacts with an ion to produce H2O2 (hydrogen peroxide) |
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Term
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Definition
| causes adherence of phagocyte to pathogen. Becomes coated with antibodies and complement proteins |
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Term
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Definition
1. Phagocyte adheres to pathogens or debris
2. Phagocyte forms pseudopods that eventually engulf the particles forming a phagosome
3. Lysosome fuses with the phagocytic vesicle, forming a phagolysosome.
4. Lysosomal enzymes digest the particles, leaving a residual body.
5. Exocytosis of the vesicle removes indigestible and residual material |
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Term
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Definition
1. NK cell releases perforins, which polymerize and form a hole in the enemy cell membrane
2. Granzymes from K cell enter perforin hole and degrade enemy cell enzymes
3. Enemy cell dies by apoptosis
4. Macrophage engulfs and digests dying cell |
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Term
| Cardinal signs of inflammation |
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Definition
| Redness, Heat, Swelling, Pain, (sometimes impairment of function) |
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Term
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Definition
| histamine (from mast cells), blood proteins, kinins, prostaglandins, leukotrienes, and complement |
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Term
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Definition
| dilation of arterioles, hyperemia, increased permeability of local capillaries and leakage of exudate |
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Term
| steps for phagocyte mobilization |
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Definition
1. Leukocytosis-- neutrophils enter blood from bone marrow
2. Margination-- Neutrophils cling to capillary wall
3. Diapedesis-- Neutrophils flatten and squeeze out of capillaries
4. Chemotaxis-- Neutrophils follow chemical trail |
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Term
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Definition
attack microorganisms directly
hinder microorganisms' ability to reproduce
block viruses |
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Term
| Process of antiviral proteins |
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Definition
1. Virus enters cell.
2. Interferon genes switch on.
3. Cell produces interferon molecules.
4. Interferon binding stimulates cell to turn on genes for antiviral proteins
5. Antiviral proteins block viral reproduction |
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Term
| Classical pathway of complement activation |
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Definition
Antibodies bind to invading organisms
C1 binds to the antigen-antibody complexes (this is called complement fixation) |
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Term
| Alternative pathway of complement activation |
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Definition
| Triggered when activated C3, B, D, and P interact on the surface of microorganisms |
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Term
| What does an activated complement do? |
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Definition
Enhances inflammation, promotes phagocytosis, causes cell lysis, Immune clearance
MAC (membrane attack complex) |
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Term
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Definition
systematic response to invading microorganisms
leukocytes and macrophages exposed to foreign substances secrete pyrogens
Moderate fever is beneficial because it increases the metabolic rate of cells, which promotes healing |
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Term
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Definition
| Can be complete or incomplete. They are substances that can mobilize the adaptive defenses and provoke an immune response |
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Term
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Definition
Important for immunogenicity and reactivity
Examples: foreign protein, polysaccharides, lipids, and nucleic acids |
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Term
| Incomplete antigens AKA haptens |
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Definition
small molecules (peptides, nucleotides, and hormones) not immunogenic by themselves
examples: poison ivy, animal dander, detergetns, and cosmetics |
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Term
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Definition
| Coded for by genes of the major histocompatibility complex (MHC) and are unique to an individual "cellular dog-tags" |
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Term
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Definition
Class I MHC proteins, found on virtually all body cells
Class II MHC proteins, found on certain cells in the immune response |
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Term
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Definition
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Term
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Definition
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Term
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Definition
Antigen-presenting cells
Dendritic cells in connective tissues and epidermis
Macrophages in connective tissues and lymphoid organs
B cells
antigens are chopped up and the fragments are put on the cell membrane of the APC and are presented to immune cells |
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Term
| When they mature, Lymphocytes have: |
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Definition
| Immunocompetence (the ability to recognize and bind to a specific antigen) and Self-tolerance (unresponsive to self-antigens) |
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Term
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Definition
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Term
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Definition
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Term
| Maturation of lymphocytes |
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Definition
1. Lymphocytes destined to become T cells migrate (in blood) to the thymus and develop immunocompetence there. B cells develop immunocompetence in red bone marrow
2. Immunocompetent but still naive lymphocytes leave the thymus and bone marrow. They "seed" the lymph nodes, spleen, and other lymphoid tissues where they encounter their antigen
3. Antigen-activated immunocompetent lymphocytes (effector cells and memory cells) circulate continuously in the bloodstream and lymph and throughout the lymphoid organs of the body |
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Term
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Definition
| T cells must recognize self major histocompatibility proteins. Failure to recognize self-MHC results in apoptosis. Recognizing self-MHC results in MHC restriction-- survivors are restricted to recognizing antigen on self-MHC. Survivors proceed to negative selection |
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Term
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Definition
| T cells must not recognize self-antigens. Recognizng self-antigen results in apoptosis. This eliminates self-reactive T cells that could cause autoimmune diseases. Failure to recognize (bind tightly to) self-antigen results in survival and continued maturation |
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Term
| What happens to self-reactive B cells |
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Definition
1. Eliminated by apoptosis (clonal deletion) or
2. Undergo receptor editing
3. Are inactivated (anergy) if they escape from the bone marrow |
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Term
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Definition
Uses lymphocytes, APC's, and specific molecules to identify and destroy non-self substances
Depends upon the ability of its cells to recognize antigens by binding to them and communicate with one another so that the whole system mounts a specific response |
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Term
| Humoral Immunity Response |
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Definition
Antigen challenge
If the lymphocyte is a B cell, the antigen provokes a humoral immune response |
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Term
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Definition
1. antigen recognition
2. antigen presentation
3. clonal selection
4. differentiation
5. attack |
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Term
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Definition
| Immunocompetent B cells exposed to antigen. Antigen binds only to B cells with complementary receptors |
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Term
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Definition
| B cell internalizes antigen and displays processed epitope. Helper T cell binds to B cell and secretes interleukin |
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Term
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Definition
| Interleukin stimulates B cell to divide repeatedly and form a clone |
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Term
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Definition
| Some cells of the clone become memory B cells. Most differentiate into plasma cells |
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Term
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Definition
| Plasma cells synthesize and secrete antibody. Antibody employs various means to render antigen harmless |
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Term
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Definition
most clone cells become plasma cells
Secreted antibodies (circulate in blood or lymph, bind to free antigens, or mark the antigens for destruction)
Clone cells that do not become plasma cells become memory cells |
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Term
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Definition
occurs on the first exposure to a specific antigen.
Antigen binds to a receptor on a specific B lymphocytes, which activates them, then plasma cells secrete antibodies or become memory B cells |
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Term
| Secondary immune response |
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Definition
happens on re-exposure to the same antigen
memory cells produce plasma cells that produce antibodies |
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Term
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Definition
Naturally acquired: infection; contact with pathogen
Artificially acquired: vaccine; dead or attenuated pathogens |
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Term
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Definition
Naturally acquired: antibodies pass from mother to fetus via placenta or to infant in her milk
Artificially acquired: injection of immune serum (gamma globulin) |
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Term
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Definition
Immunoglobulins- gamma globulin portion of blood
Capable of binding specifically with antigen detected by B cells |
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Term
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Definition
| pentamer released by plasma cells during the primary immune response |
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Term
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Definition
| dimer that helps prevent attachment of pathogens to epithelial cell surfaces |
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Term
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Definition
| monomer attached to the surface of B cells, important in B cell activation |
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Term
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Definition
| monomer that is the most abundant and diverse antibody in primary and secondary response; crosses the placenta and confers passive immunity |
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Term
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Definition
| monomer that binds to mast cells and basophils, causing histamine release when activated |
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Term
| Defensive mechanisms used by antibodies |
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Definition
Precipitation (antibodies bind to the soluble antigens and they precipitate out of solution, making it easier to phagocytize)
Lysis (complement fixation and activation causes lysis)
Agglutination (antibodies bind the same receptor on more than one cell-bound antigen, causing clumping)
Neutralization (block specific sites on pathogen) |
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Term
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Definition
cell differentiation glycoproteins, along with T cell antigen receptors, are the two types of surface receptors of T cells that provide defense agains intracellular antigens
CD4 cells become helper T cells
CD8 cells become cytotoxic T cells that destroy cells harboring foreign antigens. Other types are Regulatory T cells and memory T cells |
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Term
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Definition
immunocompetent T cells are activated when their surface receptors bind to a recognized antigen
must simultaneously recognize Nonself (the antigen) and Self (an MHC protein of a body cell) |
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Term
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Definition
1. Endogenous antigen is degraded by protease
2. Endogenous antigen peptides enter ER via transport protein
3. Endogenous antigen peptide is loaded onto class I MHC protein
4. Loaded MHC protein migrates in vesicle to the plasma membrane, where it displays the antigenic peptide |
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Term
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Definition
1a. Class II MHC is synthesized in ER
1b. Extracellular antigen is phagocytized
2a. Class II MHC is exported from ER in a vesicle
2b. Phagosome merges with lysosome, forming a phago-lysosome; antigen is degraded
3. Vesicle fuses with phagolysosome. Invariant chain is removed and antigen is loaded.
4. Vesicle with loaded MHC migrates to the plasma membrane |
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Term
| T cell activation: antigen binding |
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Definition
MCH restriction: CD4 cells bind to antigen linked to class II MHC proteins of APC and CD8 cells are activated by antigen fragments linked to class I MHC of APCs
Dendritic cells are able to obtain other cells' endogenous antigens by: engulfing virus-infected or tumor cells and importing antigens through temporary gap junctions with infected cells
Antigen binding stimulates the T cell, but co-stimulation is required before proliferation can occur |
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Term
| T cell activation: Co-stimulation |
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Definition
Requires T cell binding to other surface receptors on an APC
Cytokines trigger proliferation and differentiation of activated T cells |
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Term
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Definition
play a central role in the adaptive immune system
once primed by APC presentation of antigen, the help activate & proliferate T & B cells and activate macrophages & recruit other immune cells
Without Helper T cells, there is no immune response |
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Term
| Role of helper T cell in humoral immunity |
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Definition
Th cell binds with the self-nonself complexes of a B cell that has encountered its antigen and is displaying it on MHC II on its surface
Th cell releases interleukins as co-stimulatory signals to complete B cell activation |
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Term
| Role of helper T cell in cell-mediated immunity |
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Definition
Previously activated Th cell binds dendritic cell
Th stimulates dendritic cell to express co-stimulatory molecules needed to activate CD8 cell
Dendritic cell can now activate CD8 cell with the help of interleukin 2 secreted by Th cell |
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Term
| Role of Cytotoxic T cells |
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Definition
Directly attack and kill other cells
Lethal hit: Tc releases perforins and granzymes by exocytosis, perforins create pores through which granzymes enter the target cell, granzymes stimulate apoptosis |
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Term
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Definition
| Dampen the immune response by direct contact or by inhibitory cytokines. Important in preventing autoimmune reactions |
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Term
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Definition
| From one body site to another |
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Term
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Definition
| From one identical twin to the other |
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Term
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Definition
| Graft from another person |
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Term
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Definition
| graft from another animal species |
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Term
| How do you prevent transplant rejection? |
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Definition
immunosuppressive therapy for long enough for the body to tag the new tissue as its own
Corticosteroid drugs to suppress inflammation, antiproliferative drugs, immunosuppressant drugs |
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Term
| Severe Combined Immunodeficiency Syndrome |
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Definition
Deficit in B and T cells
Abnormalities in interleukin receptors
Defective adenosine deaminase enzyme
"Boy in the bubble"
Vulnerable to opportunistic infections |
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Term
| Acquired Immune Deficiency Syndrome--- AIDS |
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Definition
interferes with the activity of helper T cells
characterized by severe weight loss, night sweats & swollen lymph nodes
Opportunistic infections (pneumonia, Kaposi's sarcoma) |
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Term
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Definition
Enters the cell & uses reverse transcriptase to produce DNA from viral RNA
Depresses cell-mediated immunity & destroys Th cells |
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Term
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Definition
| antiviral drugs, reverse transcriptase inhibitors, protease inhibitors, Fusion inhibitors that block HIV's entry to helper T cells |
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Term
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Definition
Immune system loses the ability to distinguish self from foreign
Examples: multiple sclerosis, myasthenia gravis, Graves' disease, Type 1 diabetes mellitus, lupus, rheumatoid arthritis, etc. |
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Term
| How do autoimmune diseases happen? |
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Definition
Foreign antigens may resemble self-antigens
New self-antigens may appear, generated by...
Release of novel self-antigens by trauma of a barrier |
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Term
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Definition
Immune responses to a perceived (otherwise harmless) threat
Antibodies cause immediate and subacute hypersensitivities and T cells cause delayed hypersensitivity |
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Term
| Immediate Hypersensitivity |
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Definition
begin seconds after contact
involves IL-4 secreted by T cells which stimulates B cells to produce IgE, which causes release of histamine |
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Term
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Definition
systemic response to allergen in the blood
constriction of bronchioles, sudden vasodilation & fluid loss from the bloodstream, hypotensive shock & death
treat with epinephrine |
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Term
| Type II Subacute hypersensitivities |
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Definition
caused by IgM and IgG transferred via blood plasma or serum
Slow onset (1-3 hours) and long duration (10-15 hrs) For example mismatched blood transfusion |
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Term
| Type III subacute hypersensitivities |
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Definition
antigens are widely distributed thru body
insoluble antigen-antibody complexes form
Intense inflammation, local cell lysis, and death
Example: systemic lupus erythematosus |
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Term
| Delayed Hypersensitivities (Type IV) |
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Definition
slow onset (1-3 days)
mechanism depends on helper T cells
Cytokine-activated macrophages and cytotoxic T cells cause damage
Example: poison ivy |
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