Lecture 9: Specific Resistance and the Immune System
Terms
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- Name three components of blood
-
- serum
- clotting agents
- cells - Serum is the liquidy portion of blood. It contains what 5 things?
- minerals, salts, glucose, proteins, water
- clotting agents contain what two things?
- fibrinogen and prothrombin
- what two things make plasma?
- serum + clotting agents = plasma
- serum + clotting agents = ?
- plasma
- Name the 3 cell types
-
erythrocytes (red blood cells)
platelets (helps w/ clotting)
leukocytes (white blood cells) - Name the two types of leukocytes (white blood cells).
-
PMN (polymorphonuclear)
Mononuclear cells - What three cells make up PMN (polymorphonuclear) cells or granulocytes?
- Neutrophils, eosinophils, basophils
- What two cells make up Mononuclear cells?
-
Monocytes (become macrophages)
Lymphocytes (T cells, B cells (major players in immune system) - Name the two lyphocytes
-
T cells
B cells
(major players in immune system) - Antigen
- Macromolecule that elicits immune response (protein, polysaccharide) are antigens.
- Macromolecule that elicits immune response (_____, _____) are antigens.
- protein, polysaccharide
- Name an antigenic determinant.
-
Epitopes
Epitopes are antigenic determinants taht are subsets of antigens - The particular unique ____ (6-8amino acid, or monosaccharide unit) on an antigen that elicits a specific immune response.
- chemical group
- The particular unique chemical group(______, or ______) on an antigen that elicits a specific immune response.
- 6-8amino acid, or monosaccharide unit
- Antibodies. ______ that are produced in response to foreign antigens.
- soluble proteins
- Antibodies are soluble proteins that are produced in response to foreign antigens. They ____ and _____ epitopes of antigens.
- recognize and bind
- B lymphocytes are found in ______ immunity
- antibody-mediated
- B lymphocytes produce _____
- antibodies that provide resistance to disease
- Cytotoxic T lymphocytes are used in ______ immunity
- cell-mediated
- Cytotoxic T lymphocytes provides reistance through _______
-
direct cell-to-cell contact.
cytotoxic T cells bind to cells that have been affected and kills them.
perforin (pops the cell)
granzyme - Immune Response. In order for B cells and T cells to destroy invading organisms that are free in body solutions or hiding in cells, they must be taught what to attack--they must be presented with a ____
- target
- What are the three key words to remember with immune response?
- recognize, eradicate, remember
- 'See' part of an invader (antigen) in order to ______
-
destroy the entire invader
*seeing involves protein-protein interaction - MHC: major histocompatibility complex proteins. On all cells (define 'self'). Enormous variety (____different genes, ____ forms of each gene)
-
20
50 - There are two classes of MHC proteins. Class I MHC is found on what?
- virtually all cells of the body
- Class III MHC is found on?
- B-lymphocytes, macrophages
- Class I MHC binds _____
- CD8+
- Class II MHC binds _____
- CD4+
- Antibody-mediated or cell-mediated immunity begins with ______
- phagocytosis
- ______ or _______ immunity begins with phagocytosis
- antibody-mediated or cell-mediated immunity
- Antigens are broken down by phagocytosis. Epitopes are displayed on the surface of APC (antigen presenting cells) in context of MHC. Transport to ____
- lymphoid organs
- Helper T cells have a _____ coreceptor and binds MHC class ____
-
CD4
Class II MHC - Cytotoxic T cells have a _____coreceptor and binds MHC class ____.
-
CD8
Class I MHC - 1st step to cell-mediated immunity: Antigen displayed on APC (antigen presenting cell) in context of MHC II to ________
- effector T
- 2nd step to cell-mediated immunity: Helper T (CD4+) binds MHC II on _____. Helper T secretes _____.
-
macrophage
IL-2 (interleukin-2) - 3rd step to cell-mediated immunity: IL-2 stimulates effector T to become _______ (for now) or ______ (for later)
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cytotoxic T
memory T - 4th step to cell-mediated immunity: cytotoxic T uses _____ receptor to recognize antigen displayed in MHC___.
-
CD8
MHC I - 5th step in cell-mediated immunity: cytotoxic T secretes ______ and zaps virus infected cell
-
perforin
also: granzyme - CLonal Selectioni is the process of _____
- picking out the right antibody
- Goal of Antibody-mediated immunity.
- produce antibodies that reacts with toxins, antigens on microbial surfaces, microbial structures
- In clonal Selection, there are many B cells, but each B cell only makes one type of ____
- antibody
- Only B cell with complementary ____binds antigen
- receptor
- In Clonal selection, B cells are ____ and _____out
- activated and selected out
- Give a general summary of clonal selection.
-
1) Antigens enter the lymphoid organ
2) Lymphoid organs conatin many B cells with different surface receptors (antibody molecules)
3) When the epitope of the antigen binds to the correct B cell, it is "selected out." The cell undergoes division and enlarges to become a clone of activated B cells.
4) The activated B cells then interact with helper T lymphocytes. T cells secrete cytokines that cause B-cell division and differentiation into plasma cells and memory B cells.
5) Plasma cells secrete the antibodies that function in antibody-mediated immunity. The antibodies recognize the same epitope originally bound to B-cell receptors. - Antibody-Mediated Immunity. Antigen Presenting Cell displays antigen in context of ____ to ____
- MHC II to helper T
- APC display antigen in context of MHC II to helper T. Binding activates helper T with assistance of ____.
- IL-1
- Activated helper T binds _______ in antibody-mediated immunity.
- B lymphocytes
- B-cells differentiate into antibody secreting _____
- plasma cells
- Describe the process of antibody-mediated immunity
-
1) The antigen-receptor complex has been taken into the selected B lymphocyte, and the antigen peptide is now displayed on the B cell's surface within the class II MHC protein.
2) Meanwhile, an antigen-presenting macrophage has activated a helper T lymphocyte. Interleukin-1 from the macrophage assists the activation.
3) A clone of activated helper T cells results from the activation.
4) The activated helper T cells bind with the selected B cells. The binding takes place at the MHC II/peptide complex.
5) The binding spurs the B cells to enlarge and divide into a clone of plasma cells and memory cells.
6) The plasma cells secrete antibodies that enter the body's circulation and find their way to antigen-bearing microorganisms. Interaction with the microorganisms lead to their destruction and a specific immune defense. - After the initial antigenic stimulation, IgM is the first antibody to appear in the circulation. Initially, it is the principal component of the primary antibody response. Later, IgM is supplemented by IgG. On a second or ensuing exposure to the same ant
- The production of IgG is more rapid, and the concentration in the serum reaches a higher level than previously. Thus, the IgG antibody is more concentrated in the secondary anitbody response.
- The antibody molecule is a protein consisting of _______: two light chains and two heavy chains connected by _____ (S-S) linkages. The heavy chains bend at a hinge point
-
four polypeptide chains
disulfide - variable region
- The variable region is where the amino acid compositions of various antibodies differ
- constant region
- in the constant region, the amino acid compositions are similar in different antibodies
- On treatment with _____ enzyme, cleavage occurs at the hinge point, and three fragments result: two identical Fab fragments and one Fc fragment
- papain
- On treatment with papain enzyme, cleavage occurs at the hinge point, and three fragments result. What are they?
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Two identical Fab fragments and one Fc Fragment
Fab= fragment antibody binding
Fc= fragment crystalline - IgM
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macroglobulin
1st to appear in circulation, primary response - IgG
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gamma globulin
Secondary response, upon re-infection, IgG made by memory cells - IgA
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found in bodily secretions (colostrum) protection in body cavities possibly by inhibiting attachment of parasites. prevent illness.
When mother has baby, premilk is colostrum. It contains IgA antibody that protects baby. - IgE
- role in allergic rxns
- IgD
- membrane antibody. function unclear
- What are the five types of antibodies?
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IgM
IgG
IgA
IgE
IgD
MGAED
(My guman ate every day) - What are the four heavy chain proteins?
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V, D, J, C
v= variable
d= diversity
j= joining
c= constant - What are the four light chain proteins?
- V, J, C
- There are two heavy chains and two light chains for antibodies. Generate antibody diversity by a process called ____
- somatic recombination
- how many diffferent antibodies can be generated by somatic recombination?
- 200 million
- What are the five mechanisms by which antibodies interact with antigens?
-
- viral inhibition
- neutralization
- opsonization
- agglutination
- precipitation - The five mechanisms by which antibodies interact with antigens all enhance ____
-
phagocytosis.
opsonins encourage phagocytosis by forming a bridge between parasites and receptor sites on the phagocyte - viral inhibition
- antibodies react with molecules at the viral surface and prevent the viral attachment to cells.
- neutralization
- antibodies called antitoxins combine specifically with toxins, thereby neutralizing them
- opsonization
- antibodies (called opsonins) coat bacteria, preventing bacterial attachment to cells
- agglutination
- agglutinins combine with antigens on the cell surface and bind the cells together or restrict movement
- precipitation
- precipitins combine with dissolved antigens to form lattice-like arrangements that precipitate out of solution
- In the classical pathway of complement activity, what happens first? (antibody molecules attach to the antigens on the pathogen's _____)
- cell membrane
- In the classical pathway of complement activity, what happens second? (______ link two antibody molecules together)
- complement proteins
- In the classical pathway of complement activity, what happens third? (Activated complement proteins attach to the pathogen's membrane in step-by-step sequence, forming a _____)
- membrane attack complex
- In the classical pathway of complement activity, what happens last? (The attack complex results in _____ in the membrane causing ____ by water loss)
-
pores
cell lysis - Describe the classical pathway of complement activity.
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1) Antibody molecules attach to the antigens on the pathogen's cell membrane.
2) complement proteins link two antibody molecules together.
3) activated complement proteins attach to the pathogen's membrane in step-by-step sequence, forming a membrane attack complex
4) the attack complex results in pores in the membrane causing lysis by water loss