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81 Cards in this Set

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Define determinant or epitope
the smallest identifable part of an antigenic molecule that can be recognized by a given T or B cell receptor
antigen
An antigen is a molecule that reacts with a specific component of adaptive immunity. These components are either antibody molecules or antigen-binding receptors on B or T lymphocytes
immunogen
Immunogens are antigens that can induce an immune response
hapten
Haptens are small molecules that are not naturally immunogenic; the best examples are small drugs
tolerogen
are molecules that can stimulate immune responses and serve as targets of those responses , but on re-exposure reduced responsiveness
Pattern-recognition receptors
Used by the innate system that are genetically encoded and expressed by a variety of leukocytes
Antigens may be
proteins, carbohydrates, lipids,or combinations such as glycoproteins and glycolipids
epitope or determinant
the smallest identifiable part of an antigenic molecule that can be recognized by a T or B cell receptor
immunogens
antigenic molecules that can both stimulate an immune response and be a target of an immune response
haptens
small molecules that by themselves cannot stimulate immune responses but can be recognized by the immune system if bound to an immunogenic molecule
what cell surface molecules are useful in distnguishing leukocytes?
Immunoglobins, CD cluster of differentiation receptors, major histocompatibility MHC molecules
superantigen
molecule that stimulates T cell subsets by binding to parts of the T cell receptor other than the antigen binding groove
In adaptive immunity antigenic determinants are recognized by....
Innate immunity receptors
A. B cell receptor and T cell receptors ,

B. Toll receptors and Broad Molecular Patterns
If a person has blood type AB, what antibodies do they produce
neither anti-A or anti-B
what are some of the effector functions of immunoglobins?
-opsonization by binding to FcR to aid in killing bacteria
- complement fixation
-passage through placenta
what are the five classes of Immunoglobins?
IgG, IgM, IgD, IgA, IgE
For the structure of each Ig molecule how many domains are present?
Two on the light chain: VL & CL

Four on the Heavy chain: Vh & CH1, CH2, CH3, and maybe CH4
How does papain digest Ig?
Papian cleaves Ig in the hinge region of the molecule.
Valence=1 because the is only one antigen binding site and specifity is detemined by Vh &VL also the Fc region is still in tack
Pepsin digestion of Ig?
F(ab')2, valence=2
what region of Ig mediate effector function?
Constant regions
what are the two types of light chains?
Kapppa or lambda
60:40 ratio except in malignacny like multiple myeloma or B cell leukemia
what are some characteristics of IgG?
-It has only one unit
-Four subclasses
-major serum Ig
-Can cross the placenta and does not requires Ag binding
-Fixes complement(IgG4)
_Binds to Fc receptors(IgG2,IgG4)
-Longest half-life
what are the characteristics of IgA?
-in serum it is a monomer
-in secretions(slgA) it is larger- second highest in serum,

- dimer with or without J chain
-with secretory componect
slgA found in.....
tears, saliva, gastric and pulmonary secretions
-does not fix complement
-binds to Fc receptors on some cells
Where are IgD found?
B cell surface Ig (usually with IgM monomer)
-does not bind complement
IgE antibody has what extra?
- exta domain
-least common serum Ig
- Allergic rxns
-In parasitic infections they bind to Fc receptors of eosinophils
- does not fix complement
isotypic
the class or subclass of an Ig
allotype
a structural site on the heavy chain of a particular Ig class or onthe light chain that differs among indiv or inbred lines of the same species Used as markers
idiotype
an antigenic determinant on a specific antibody, characteristic of that antibodyans different from others even of the same isotype and allotype, idiotype are usually located in or near the antigen binding site
allellic exclusion
The inactivation of one set of the chromosomes in B cell, because only one kind of light chain and one kind of heavy chain can be expressed
what is the normal response to an immunogen?
Polyclonal response-many clones of B cells making different antibodies
where are monoclonal antibodies produced ?
Monoclonal antibodies are produced in the lab by making mouse hybridomas- product of one B cell all molecules identical
How to generate a polyclonal immune response?
-Immunize an animal or a human with an immunogen
-Collect serum (separated from clotted blood) at a time when antibodies are expected
-Check serum for antibodies by serological tests
-If antibodies are found=antiserum
-If antibodies not found:
Boost a second time
Use an adjuvant
Heterogeneous Ig
Ig antibodies are normally heterogeneous, but there are five classes and subclasses
Homogeneous Ig
Results from Myeloma
multiple myeloma
-Malignancy of a B cell
-Patient produces extremely high levels of IgM (Waldenstrom’s macroglobulinemia), IgG, or IgA (occasionally IgD or IgE)
-High serum levels due to large number of monoclonal population B cells
Results in immunodeficiency and other symptoms
Nature of Ag/Ab Reactions due to epitope-paratope interactions
Non-covalent interactions-
Hydrogen bonds
Electrostatic bonds
Van der Waal forces
Hydrophobic bonds
what are the four types of hypersentivity reaction?
Type I mediated by IgE

Type II mediated by antibodies

Type III medatied by immune complexes

TypeIV mediated by cells
Hypersentivity occurs as a result of...
secondary response
Homocytotropic
IgE binds to Fc receptors FcRe on cells in the absence of antigen
What happens when IgE antibodies on the surface of mast cells,basophils are cross linked by allergen?
1. the preformed mediator histamine is rapidly released
2. synthesis of other non-preformed mediators is initiated
what is atopy?
genetic tendency to make IgE in response to allergens
What is the normal concentration of IgE in the blood?

half-life in circulation?
half-life bound to cells?
- <1ug/ml in the blood

- 2 to 3 days in circulation
- 3 to 4 wks bound to cells
IgE can be measured by?
RIST-total circulating IgE

RAST-specific circulating IgE
Name the late phase derived mediators od hypersensitivity reaction?
Leukotrienes- C4,D4,and E4 generated by the metabolism of arachidonic acid,

Prostaglandin D2
Platelet activating factor
True or False. Endothelial cells are important components of the innate immunity be/c they release proteins and peptides known as cytokines and chemokines
True
These are lymphocytes that have the own receptors KIR and KAR that recognize virally infected cells and tumor cells
NK lymphocytes part of the adaptive immune response can directly kill infected cells without phagocytosis
Toll receptors
These are receptors that recognize PAMP which include LPS,lipopeptide,peptidoglycan which are unique to bacteria and unmethylated DNA and dsRNA which are unique to viruses
True or False. Epithelial and endothelial cells secrete antibacterial peptides such as defensins and intergrins
True
what are the 3 primary effector cells in the innate immune system?
Macrophages(monocytes), neutrophils, and NK cells
which cytokines are secreted by macrophages ?
TNF alpha and IL-1 which regulate fever and effect the hypothalamus.
how many days does the neutrophil live?
1 to 3 days - they are the key mediators of acute inflammation
interferon
A class of small protein and glycoprotein cytokines (15–28 kD) produced by T cells, fibroblasts, and other cells in response to viral infection and other biological and synthetic stimuli. Interferons bind to specific receptors on cell membranes; their effects include inducing enzymes, suppressing cell proliferation, inhibiting viral proliferation, enhancing the phagocytic activity of macrophages, and augmenting the cytotoxic activity of T lymphocytes.
what are the three main functions of acute inflammatory response?
-Acute inflammatorey exudate which carries proteins, fluid, and cells from local blood vessels into damaged area to mediate local defenses
- destruction of the infective agent
-damaged tissue can be broken down and removed
what are some physical changes that will happen in inflammatory response?
-changes in blood flow
- increased permeability of blood vessels
- escape of cells from the blood into the tissues
define hypersensitivity?
-it occurs when an altered state of immunoliogical responsiveness causes an inappropriate or excessive immune rx which damages the tissues
Stages of B cell development: combination of gene segments encoding heavy chain u had begun , but heavy chain not yet produced
Pro B cell
This stage of B cell development: heavy chain u is completely rearranged; heavy chains are in the cytoplasm ; surrogate light chain
Pre B cell
Stage of B cell: expression of monomeric IgM and serves asn the antigen receptos for the cell
Immature B cell
These immature B cell mature in the spleen and express both IgM and IgD- they form the BCR complex
Mature B cell
Mature B cells are positive for
CD19 and CD20
When antigen binds to the BCR on mature B cell....
B cell divide and differentiate
After antigen Binds to Bcell
- B lymphoblast is formed, more ribosomes to make Ig:n clonal expansion
What happens after 4-5 days to the B lymphoblast
it becomes a plasma cell for 2-3 days then die
memory cells
the portion of lymphoblast that do not become plasma cells; they have IgG, IgA and IgE on their surface
CD 10
on pre B cells
CD 34
-on Stem cells
Bcell receptors
- Fc Receptor
- Complement receptor
- MHC molecules
How can a T cell recognize an antigen?
The antigen must be present on a cell membrane, in the binding groove of either class I or class II MHC
what are the two types of antigen receptors?
-alpha beta ( mostly)
-gamma delta
The Tcell receptors are also associated with what that is involved in signal transduction?
The CD3
Early cell differentiation marker for both B and T cell
-CD1
Found on all human T cells regardless of stage of diffferentiation
- CD2
Is an enzyme that is present only in cortical thymocytes and early progenitors of B cells. Plays a role in generating diversity of V sequences in the BCR and TCR
TdT
Binds to class II MHC molecules
CD4 ( helper or DTH)
Binds to class I MHC molecules
CD8
Class I are found where
-on all cells exceptn neurons and striated muscles
-unique alpha chain, unique to self w/ constant beta2 microglobin
Class II are found
- B cells , macrophages, dendritic cells, activated Tcells
- have a alpha and beta chain
The process by which cells with receptors that do no recognize self or bind too strongly to self MHC are eliminated
Positive selection
what is another name for MHC?
HLA human leukocyte antigen
true or false. gene rearrangement occurs prior to antigen exposure
true