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127 Cards in this Set
- Front
- Back
Immune system specificity:
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The ability to recognize a pathogen and fight it individually.
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What are the two different branches of the specific immune system?
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-The Humoral Immune System (Antibody-Mediated)
-The Cell-Mediated Immune System |
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The Humoral Immune System responses deal with:
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B-Cells and their eventual production of antibodies.
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The Cell-Mediated Immune System responses deal with:
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T-Cells
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Is there some crossover between the branches?
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Yes, they are not completely distinct from one another.
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Define Immunity:
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The bodies defense against a particular pathogen.
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Define Cell-Mediated Immunity:
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Deals with T-Cells
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Define Humoral Immunity:
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Deals with B-Cells and their production of antibodies.
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Define Antigens (Ag):
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Something that triggers an immune response; whatever is causing the immune system to respond.
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Define Antibodies (Ab):
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Proteins made by B-Cells to attack the Antigens.
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Define Antigenic Determinant (Epitope):
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The precise part of the Antigen that the Antibody binds to.
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If the Immune System is responding to a bacterial cell, the entire bacterial cell is the _____________, and the parts on its surface where the antibodies will bind are called _____________.
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ANTIGEN; ANTIGENIC DETERMINANTS / EPITOPES
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Where the Antibody attaches to the Antigen is called:
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The Antigenic Determinant/Epitope.
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What kind of things can serve as Antigens?
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Anything; anything that triggers immune response.
-Bacteria -Viruses -Foreign human or animal cells -Pollen or Dust |
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What sorts of structures make good Antigens, ie. stimulate a large immune response?
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Generally, the LARGER, more COMPLEX the molecule, the stronger the immune response.
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What sorts of structures make bad Antigens, ie. don't stimulate a large immune response?
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Smaller molecules or molecules with a repetitive structure.
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Why do smaller molecules or molecules with a repetitive structure stimulate a smaller immune response?
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Because there is only one Antigenic Determinant over and over.
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The importance of having a good Antigen is seen in:
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Vaccine technology, where it is important to choose a large, complex molecule with lots of Antigenic Determinants on it to stimulate a large immune response and get lots of memory cells from it.
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Describe the Antibody Structure:
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The Antibody is made of 4 protein chains:
-2 are identical HEAVY chains (having the same amino acid sequence) -2 are identical LIGHT chains The heavy chains are attached together, and the Light chains are attached to the heavy chains. |
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Describe the regions of the Antibody:
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There are two regions on both the heavy and light chains:
-the Constant region -the Variable region |
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Describe the Constant region of Antibodies:
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The constant regions have the exact same amino acid sequence. All Antibodies of the same class have an IDENTICAL constant region.
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The area at the tip of both the heavy and light chains of the antibody:
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the Variable region.
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What does the Variable region determine?
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The Variable regions controls what the antibody binds to; ie. it's specificity.
-one antibody binds to E. coli and nothing else, another antibody has a different variable region and binds to Salmonella and nothing else. |
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What controls the specificity of antibodies? ie, what the antibody can bind to?
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The variable regions
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On the Antibody:
-The top of the Y structure is called: -The bottom of the Y structure is called: |
-The top of the Y structure is called: the Antigen Binding Fragment (Fab).
-The bottom of the Y structure is called: the Crystallizable Fragment (Fc). |
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On Antibodies, the binding site for cells is on the:
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Crystalizable Fragment
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What are the 5 classes of Antibodies?
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-IgG
-IgA -IgM -IgE -IgD |
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Antibodies are also called:
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Immunoglobulins
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Describe IgG:
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Exist as Monomers; known for being the Memory Antibody
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Describe IgA:
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Exist as Dimers; "the secreted antibody." Found in all body secretions:
-Saliva -Mucus -Cervical secretions |
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IgA Dimers are composed of:
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2 monomers attached together through a protein called the J-chain.
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What is unique about IgA?
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It has the Secretory Component; a molecule added in that allows IgA to be secreted in body fluids.
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Describe IgM:
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Exist as a Pentamer; five monomers held together via J-chain. The first antibody made during immune response; can serve as B-Cell receptor.
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Describe IgD:
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Exists as a monomer; Is the receptor on B-Cells.
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Which Antibodies are monomers?
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IgG, IgE, & IgD
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Which Antibody is the first one made during immune response?
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IgM
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Describe the B-Cell receptor:
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The B-Cell receptor is simply an IgD antibody stuck on its surface.
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Describe IgE:
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Exists as monomer; specifically involved in allergy responses.
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Which antibodies bind to phagocytes?
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IgA & IgG
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Which antibodies bind to B-cells?
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IgM & IgD
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Which antibodies bind to Mast cells & Basophils?
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IgE
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What makes the classes of Antibodies?
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The Identical amino acid sequences of their Constant regions.
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Do antibodies of the same class have the same Variable regions?
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No. ie, one will have Variable regions that will bind to e. coli, while another has Variable regions to bind to Strep pneumoneae. This is what gives them their specificity.
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What are the antibodies functions?
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-Compliment Fixation(Classical pathway of triggering complement)
-Agglutination -Neutralization -Opsonization |
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Describe Opsonization:
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The enhancement of phagocytosis by coating the microbe with Compliment proteins or antibodies.
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Describe Agglutination:
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The binding of antigens together to deactivate them.
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Describe compliment fixation:
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The classical mechanism of triggering Compliment:
-The antibody binds to its antigen triggering the first Compliment protein the the cascade, C1 → Opsonization, Activation of Mast cells (triggering of Inflammation), & Cytolysis by MAC. |
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Describe Neutralization:
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When Antibodies surround the pathogen so that it can't attach to host tissues. (usually used against viruses)
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There is a repertoire of __________ in the _________.
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B CELLS in the LYMPH NODES.
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The B cell receptor on each B cell is:
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specific for a particular antigen; each one is different.
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Define Clonal Selection:
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When the B cell is activated by the antigen binding to its receptor, endocytosis, & T Helper Cell interaction.
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What happens after Clonal Selection:
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Clonal Expansion, the activated B Cell will go through cell division and give rise to two different types of cells: Memory B cells and Plasma cells.
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What then happens to the Memory B cells and Plasma cells?
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The Memory B cells hang out in the Lymph Nodes in case of future infection; the Plasma cells secrete antibodies (IgM)
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Define Clonal Expansion:
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The process after Clonal Selection where B cell division creates Memory B cells and Plasma cells.
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After an initial infection, what happens to the Plasma cells that were produced in Clonal Expansion?
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They die, but the Memory B cells live on in the Lymph Nodes waiting for possible future infection.
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What is the benefit of the Memory B cell response?
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It is much faster than the Clonal Selection/ Clonal Expansion process & can flood the body with IgG very quickly in response to infection.
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The memory response is only seen in the:
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Specific Immune system.
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Describe how the B Cell repertoire is made:
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The B cell receptor formed will determine:
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the antibody made; ie, if the receptor identifies Vibrio cholera, then it will make antibodies against Vibrio cholera.
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Are all B cells unique in their specificity?
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yes.
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How many different possibilities are there in making B cells based on receptors?
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1.92 Million
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B Cells mature in the:
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Bone marrow
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B Cell maturation is called:
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Clonal Deletion
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Describe Clonal Deletion:
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B Cells are tested to see if they interact with self tissue. Those that do are destroyed, those that pass are sent to the lymph nodes.
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What are the steps in the life of the B cell:
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1) Random production of B cell receptors
2) Clonal Deletion 3) Deployment to the Lymph Nodes to await Clonal Selection |
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How are T cells different from B cells?
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T cells cannot see antigen floating around them like B cells can. They have to have antigen presented to them on Self-MHC.
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Sometimes in medicine, MHC is called:
-Tissue-typing is called: |
Human Leukocyte Antigen (HLA)
-HLA typing |
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In tissue typing they are looking at:
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MHC (HLA), trying to identify how close the donor's MHC is to the recipient.
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What are the classes of MHC?
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MHC Class l & MHC Class ll
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Describe MHC Class l:
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MHC Class l is made and presented by all cells of the body (except RBCs).
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Describe MHC Class ll:
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MHC Class ll is made and presented by professional Antigen Presenting Cells (APCs).
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What exactly does MHC Class l present?
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MHC Class l presents intracellular antigens and cellular molecules; takes things from inside the cell and presents it on the surface of the cell.
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What exactly does MHC Class ll present?
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MHC Class ll presents bits and pieces of digested FOREIGN antigens.
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The real self-tag is:
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MHC Class l
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What binds to MHC Class l ?
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Cytotoxic T cells
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What binds to Class ll MHC?
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T helper cells
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Cytotoxic T cells bind to MHC Class __ via:
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Cytotoxic T cells bind to MHC Class l via their T CELL RECEPTOR & CD8
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T helper cells bind to MHC Class __ via:
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T helper cells bind to MHC Class ll via their T CELL RECEPTOR & CD4
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B cells are:
made in the _____________. mature in the ____________ . |
made in the: Bone marrow
mature in the: Bone marrow |
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T cells are:
made in the _____________. mature in the _____________. |
made in the: Bone marrow
mature in the: Thymus |
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T cell receptors bind specifically to both:
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the particular Antigen and self-MHC
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T cells also have additional receptors called:
These help: |
Clusters of Differentiation (CD)
These help with the interaction. |
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Cytotoxic T cells = MHC__ & CD__
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Cytotoxic T cells = MHC l & CD8
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T helper cells = MHC__ & CD__
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T helper cells = MHC ll, CD4
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What are the two main types of T lymphocytes?
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The T Helper Cells & Cytotoxic T Cells
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T Helper Cells get activated and differentiate into:
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Either:
-T helper 1 Cells -T helper 2 Cells -CD4+ T Memory Cells |
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Do you get memory cells from all of the specific immune cells?
If so, what are they? |
Yes, they are:
B Cells= Memory B Cells T Helper Cells = CD4+ T Memory Cells Cytotoxic T Cells = CD8+ T Memory Cells |
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What do the T Helper 1 & 2 Cells stimulate?
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-T helper 1 Cells: Stimulate Macrophages, Cytotoxic Ts, & other T Helper Cells.
-T helper 2 Cells: Stimulate B Cells & Suppress T Helper 1 Cells. |
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What do CD4+ T Memory Cells do?
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They wait for re-activation upon future infection.
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What do Cytotoxic T Cells do?
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They destroy foreign or abnormal cells and give rise to: CD8+ T Memory Cells
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What do CD8+ T Memory Cells do?
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They wait for re-activation upon future infection.
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Describe the T Cell Receptor (TCR):
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The T Cell Receptor has a Constant Region and a Variable Region.
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On the T Cell Receptor, what does the Constant Region and Variable Region bind to?
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The Constant Region binds to: Self-MHC
The Variable Region binds to: the Antigen. |
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How are T Cell Receptors made?
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The same way that B Cell Receptors & MHC is made, random selection of exons from genes.
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The maturation process of T Cells occurs in the ________ and is called:
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Thymus; and is called Positive Selection or Negative Selection.
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Describe:
-Negative Selection: -Positive Selection: |
-Negative Selection: T Cells with useless or dangerous TCRs are destroyed.
-Positive Selection: T Cells with good TCRs are propagated and sent to the lymph nodes and lymphoid tissues. |
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What are the APCs?
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Macrophages, B Cells, & Dendritic Cells
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Which APC's main job is to be an APC?
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the Dendritic Cell.
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APCs present antigen on:
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MHC Class ll
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What is the first step of T Helper Cell Activation?
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T Cell Receptor with the help of CD4+, binds to the Antigen on MHC Class ll being presented by the APC
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What is the second step of T Helper Cell Activation?
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After binding, the APC releases Interleukin-1 or Interleukin-4. The T Helper Cell is now activated and ready to differentiate.
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If the APC releases IL-1, then the T Helper will differentiate into a:
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T Helper 1 Cell
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If the APC releases IL-4, then the T Helper will differentiate into a:
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T Helper 2 Cell
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T Helper 1 Cells release ______ which activates:
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T Helper 1 Cells release IL-2 which activates: Macrophages, Cytotoxic T Cells, & other T Helper Cells.
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T Helper 2 Cells release ______ which activates:
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T Helper 2 Cells release IL-4 & B Cell growth factor which activates: B Cells. They also have an inhibitory affect on T Helper 1 Cells.
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Regardless of IL-1 or IL-4 differentiation, either way, these will be created:
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CD4+ T Memory Cells
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If the APC releases IL-1 then:
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The T Helper Cell differentiates into a T Helper 1 Cell, which releases IL-2 and activates Macrophages, Cytotoxic T Cells, and other T Helper Cells.
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If the APC releases IL-4 then:
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The T Helper Cell differentiates into a T Helper 2 Cell, which releases more IL-4 & B Cell Growth Factor which activates B Cells. They also inhibit T Helper 1 Cells.
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If the APC is a Macrophage or Dendritic cell, then when it interacts with the T Helper Cell it is most likely to release:
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IL-1
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If the APC is a B Cell, then when it interacts with the T Helper Cell it is most likely to release:
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IL-4
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What exactly do B Cells need to go through clonal expansion?
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They have to present the Antigen on MHC Class 2 to a T Helper Cell. The B Cell releases IL-4 turning the T Helper Cell into a T Helper 2 Cell. The T Helper 2 Cell then releases more IL-4 and B Cell Growth Factor. The IL-4 & B Cell Growth Factor cause the B Cell to go through Clonal Expansion.
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Define Cytokines:
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Chemical messenger molecules that communicate between immune cells.
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Define Interleukin-1:
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Activates T Helper Cells to become T Helper 1 Cells when produced by the bound APC.
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Define Interleukin-2:
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Produced by active T Helper 1 Cells and stimulates Macrophages, Cytotoxic T Cells, and other T Helper Cells.
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Define Interleukin-4:
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Activates T Helper Cells to become T Helper 2 Cells when produced by the bound APC. Also produced by T Helper 2 Cells to help activate B Cells.
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Define B Cell Growth Factor:
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Made by T Helper 2 Cells to activate B Cells.
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Define Interferons:
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Stimulate production of anti-viral proteins when released by other virally-infected cells.
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Define Chemokines:
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Attract leukocytes to an infection when released by Mast Cells.
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Cytotoxic T Cells bind to antigens presented on:
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MHC Class l
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Cytotoxic T Cells are activated by:
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IL-2 released from T Helper 1 Cells.
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The active Cytotoxic T Cell releases:
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Perforins & Granzymes
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What do Perforins & Granzymes do?
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Perforins lyze the bound cell & Granzymes degrade cellular proteins.
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Describe the steps in Cytotoxic T Cell activation:
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1) Cytotoxic T Cell is activated by IL-2 released from T Helper 1 Cells.
2) Self-Cell presents a piece of Intracellular Antigen on MHC Class 1. 3) Cytotoxic T Cell receptor binds to Antigen & MHC Class 1 with the help of CD8+. 4) Cytotoxic T Cell releases Perforins & Granzymes that destroy the cell. |
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Since T Helper Cells interact with MHC Class ll, they are only activated by:
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APCs
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T Helper Cells act as the _____ for the entire immune system.
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the CONDUCTOR
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Since Cytotoxic T Cells interact with MHC Class l, they can be activated by:
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any cell of the body (except RBCs).
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Which cells target and destroy cells with viral infections and cancerous cells.
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Cytotoxic T Cells.
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