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Specific (Adaptive) Immunity
Microbiology 310 Chapter 29
43
Microbiology
Undergraduate 3
12/06/2010

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Term
anamnestic
Definition
Applies to acquired immunity. Refers to the act of memory (an- amnesia or not forgetting); the increase speed and severity of reaction on repeat exposure
Term
pathology in immune system
Definition
innate : pathology rare. acquired: autoimmune response is more common
Term
purpose of antigen presenting cells
Definition
antigens are usually non soluble. this means that the APCs have to process it in order for it to reach the B cells to create antibodies
Term
antigen
Definition
any molecule that reacts with an antibody.
Term
immunogen
Definition
an antigen that creates an immune response
Term
Cell mediated
Definition
T cells.
Term
Humoral (Antibody Mediated)
Definition
B Cells
Term
epitope
Definition
antigenic determinant sites. present on antigen. stimulate the production of antibodies and bind to them
Term
haptens
Definition
small molecules that bind to antibodies but are only antigenic when combined with a larger molecule. An example is penicillin.
Term
Natural vs Artificial Acquired Immunity
Definition
Active or Passive.
Natural Active: person develops their own immune response/memory through natural exposure
Artificial Active: developing their own immune response due to artificial exposure (vaccine!)
Natural Passive: preformed immunity through colostrum
Artificial Passive: preformed immunity through plasma or immunoglobulin transplant
Term
Class 1 MHC
Definition
cell surface glycoproteins present on all nucleated cells (not on RBCs). present endogenous antigens to CD8 cytotoxic T cells
Term
Major Histocompatibility Complex
Definition
A chromosome locus that encodes histocompatability antigens
Term
Class 2 MHC
Definition
glycoproteins on antigen presenting cells. present exogenous antigens to CD4 T cells (T helper) through the T cell receptor
Term
Signals for T Cell Activation
Definition
1: antigen fragment touches receptor (brought by antigen presenting cells)2: B7 protein presented by APC (by CD28 receptor). Both signals send info into cytoplasm of T cell to produce interleukin 2mRNA. This is a form of SIGNAL TRANSDUCTION! in other words it changes gene expression for the T cell so it will do stuff
Term
Reason for 2 signals in T cell activation
Definition
Amplifies response based on severity of infection (B7 protein regulates amounts of interleukin) and also controls response and provides feedback inhibition
Term
B cell receptor
Definition
Has BCR combined with co receptors Igalpha and Igbeta on the surface membrane
Term
T helper cells and B cells
Definition
T helper cell is activated by antigen presenting cell. It proliferates and creates cytokines. It then interacts with a B cell that has the same antigen. At this point more cytokines are produced. The T helper cell's cytokines will cause the B cell to proliferate and differentiate into plasma cells (to create antibodies)
Term
Antibody structure
Definition
consists of heavy and light chains (based on # of amino acids). has disulfide bonds intramolecular and intermolecular (polypeptides in antigen). binding is reversible (non covalent). Antigen binding sites are on amino terminus. They have variable and constant regions.
Term
Affinity
Definition
strength of Ab-Ag interaction - Km value
Term
Avidity
Definition
overall ability of Ab to bind Ag at all Ag binding sites
Term
Immunoglobulin classes
Definition
IgG IgM IgA IgD IgE
Term
IgG
Definition
Most abundant human immunoglobulin in body fluids. neutralizes toxins. opsonizes bacteria. activates complement. transplacental antibody.
Term
IgM
Definition
First to appear after antigen stimulation.
Term
IgA
Definition
secretory, protects external surfaces (mucous)
Term
IgD
Definition
on B cell surface. B cell recognition of antigen
Term
IgE
Definition
Anaphylactic mediating antibody, also resists helminths
Term
Isotypes
Definition
different subtypes of immunoglobulin. Changes in disulfide bonds change protein folding and structure (also function)
Term
memory and clonal expansion
Definition
One single cell creates antibodies and clones itself including memory cells. This is why immune response is much stronger the second time of exposure.
Term
monoclonal antibody production
Definition
immortalizes antibody producing cells: a myeloma can receive mouse spleen cells DNA and create a hybridoma for cancer treatment
Term
lymphocyte clonal expansion
Definition
a single stem cell creates many distinct clones, each with a unique antigen recognition site. All self recognising cells are destroyed. when an antigen is encountered, the progenitor clone replicates to make many plasma cells.
Term
tolerance
Definition
the culling of self-recognizing lymphocytes. an autoimmune disorder may occur when these cells are not removed
Term
Antigen-Antibody Binding
Definition
precipitation, neutralization, complement fixation, agglutination, opsonization
Term
Opsonization
Definition
antibody binds to antigen on larger molecules or cells so phagocytes can find them more easily
Term
Agglutination
Definition
insoluble antigens are cross linked by the antibody creating an agglutinated mass
Term
Complement
Definition
a cascade is activated by immune complexes. lysing bacterial cells
Term
neutralization
Definition
antibody binds to antigens, preventing it from binding host cells. Usually occurs with viruses
Term
precipitation
Definition
formation of a macromolecular complex
Term
Type I Hypersensitivity
Definition
Allergic Response. Antigens are encountered and carried to lymph nodes. Here they are recognized by B cell along with Helper T cell. Plasma cells synthesize IgE which binds mast cell receptors. The mast cell primed with IgE is what is activated on repeat exposure. The allergen attaches and stimulates allergic mediators: serotonin, histamine etc. This results in allergic symptoms.
Term
Type II hypersensitivity
Definition
cytolytic/cytotoxic reaction. IgG or IgM cells are inappropriately directed against cell-surface or tissue-associated antigens. An example is blood transfusion with wrong blood type.
Term
Type III Hypersensitivity
Definition
formation of immune complexes. circulating complexes lodge into joints, kidney, skin etc. allergic mediators are released and neutrophils migrate to site of immune complex and release enzymes that destroy tissues. Arthritis is an example of this.
Term
mutliple sclerosis, rheumatoid arthritis, lupus, type 1 diabetes
Definition
autoimmune diseases.
Term
cytotoxic T lymphocyte
Definition
T cell that recognises antigen in class I MHC molecules, destroying the cell on which the antigen is displayed.
Term
The four factors that differentiate aquired from innate immunity
Definition
1. discrimination b/w self and non self based on cell surface proteins (both do discriminate though)
2. diversity: antibodies are diverse
3. specificity: immunity is selective but does not confer immunity to other pathogens
4. memory: when re-exposed the body reacts quickly enough to prevent illness
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