test 9 Flashcards
1
Q
Overview of immunity
A
- System that protects individual against invasion by microorganisms and foreign substances
- Must recognize and destroy invaders – BUT do no damage to normal body tissue
- phagocytosis and/or membrane lysis
- destruction take place at point of infection - white blood cells, antibody and the complement system – variety of chemical mediators
2
Q
Antigen
A
- anything foreign that enters the body
- can bind to antibody and/or can bind to receptors on the T or B cells
3
Q
Antigen Examples
A
- Microorganisms (bacteria / viruses / parasites / fungi / yeasts)
- Allogeneic cells (transplant or transfusion)
- Malignant cells (cells turn cancerous)
- Infected cells (cells inhabited by viruses / certain bacteria / parasites)
4
Q
Target Cells
A
- antigenic cells that will be destroyed by immune system
5
Q
Immunogen
A
- any substance that can stimulate an immune response
- all are antigenic (can bind with antibody)
- not all antigens are immunogens (not all antigens will exhibit an immune response)
6
Q
Pathogen
A
- antigen with ability to cause disease
- usually microorganism or toxin
7
Q
Leukocytes: aka. White Blood Cells
A
- Avg adult has 75 billion circulating WBCs
- NORMAL COUNT: 5,000 to 10,000 per mL
- Neutrophils: 40 to 75% of total
- Lymphocytes (T Cells / B Cells): 20 to 45%
- Monocytes: Up to 8%
- Eosinophils and basophils very little
8
Q
Granulocytes
A
- Most numerous, named for granules in cytoplasm
- hang out in the lymph nodes
- Neutrophils
- Basophils
- Eosinophils
9
Q
Monocytes
A
- dont have granules
- circulating in the blood stream
- do not enter extravascular space
- Large white cells
- Become macrophages in body tissues
10
Q
what is a monocyte called when it goes into the tissue?
A
- macrophage
- becomes a lot larger
- job is to gobble stuff up
11
Q
Lymphocytes
A
- dont have granules
- Differentiate into B- and T-cells
- specific immune response
12
Q
Granulocytes: Neutrophils
A
- Made in hematopoietic marrow
- 50% circulate
- 50% adhere to blood vessel wall
- moves from vasculature to the tissues - phagoctotic
- Produce about 100 billion per day
- First to enter infected areas
13
Q
when the body has noticed a foreign substance, what happens first
A
- neutrophils go to that area
- Attracted via chemotaxis
- Phagocytize invading organism
- Die
- Phagocytized by macrophages
14
Q
Granulocytes: Eosinophils
A
- Develop and mature in hematopoietic marrow
- Appear where FOREIGN PROTIENS and PARASITES are
- Involved in allergic reactions (secrete histamine)
- Have binding sites for specific antibodies and complement proteins
- Designed to destroy cells coated with:
- IgG antibodies
- IgE antibodies
- Complement proteins
15
Q
Where are eosinophils and what are they effective against
A
- Reside in tissues (do not circulate)
- Skin, bronchi, bronchioles - Release antitoxin (Major Basic Protein) to destroy organisms (can also destroy normal tissues)
- Very effective against parasitic worms
16
Q
Granulocytes: Basophils
A
- Least common
- Have chemotaxis and phagocytic activity
- Main fxn: RELEASE OF HEPARIN in areas of foreign invasion to prevent blood clots from forming => allows WBC to get to that area to destroy foreign organism
- Also release histamine causing vessel dilation
- Circulate in blood
- Have receptors for IgE antibody
- Similar to mast cells
- Also contain histamine granules
- Also have surface receptors for IgE antibody
- Mast cells do not circulate – remain in tissues. Basophils are NOT in tissues
17
Q
Monocytes (Macrophages)
A
- Produced in bone marrow
- Circulate immature
- Leave the blood and travel to the tissues
- Monocytes in blood for 1-2 days
- Macrophages in tissues for months to years
18
Q
Lymphocytes
A
o Specific immune response when antigen invades
o Activated when they recognize foreign matter
o Circulate in blood
o Wait in lymph nodes for antigens to appear
o Play a role in rejection of organ transplants
19
Q
T-Lymphocytes (aka. T-Cells)
A
- Once T-Cells recognize – bind antigen
- Release cytokines (interleukins) - Different types of T-cells:
- Helper T-Cells (CD-4)
- Cytotoxic T Cells (CD-8)
- Regulatory / Suppressor T Cells
- Memory T Cells
20
Q
Antibody Molecules
A
- Protein molecules: (also called) =immunoglobulin
- Produced by B lymphocyte cells (plasma cells) in response to a specific antigen
- after initial exposure, takes 14 days to reach full power (lag time) - Always present in small amounts
- blood & body tissues - Five classes IgG; IgM; IgD; IgA; IgE
- Must bind with the outer surface of the antigen to be effective
- antigen binding site unique - Cannot cross cell membranes
21
Q
Antibody Molecules function
A
- opsonize (coat antigen with antibody) antigen (mark antigen for destruction)
- activate complement cascade
22
Q
Fab portion of the B cell
A
Variable
23
Q
Fc portion of the B cell
A
constant
24
Q
surface of B cells trigger
A
production of antibodies
25
Q
B cell receptors and communication with the inside of the cell
A
- uses co-receptor to translate the signal down inside the cell
26
Q
simple function of B cell function
A
- resting B cell encounters antigen (B cell has binding site for it) and bind the antigen to the B cell binding site
- stimulates the B cell and starts to produce antibodies
- once B cell becomes activated by the atigen, it becomes a plasma cell (actively secrete antibodies)
27
Q
What cells actively secrete antibodies
A
- Plasma B cell
28
Q
When specific B cells come in contact with their specific antigen
A
- Produce more B cells that have that specific receptor which produce more antibodies
- it’s not just one B cell that produces all of the antibodies
29
Q
Opsonization
A
- Coating of antigen with antibody and complement
- Provides targeting mechanism for the phagocytic neutrophils and macrophages allowing them to bind, engulf, and destroy the antigen - Provides points where the phagocytes can attach to the antigen
- Phagocytic cells have two specific receptors on their membrane surface
- Fc receptor: binds with antibody
- C3 receptor: binds with complement
30
Q
Antigen Destruction Mediated by Antibody
A
- Opsonization
- Lysis
- complement activation leads to production of the
membrane attack complex (MAC)
- the MAC will lyse the antigens membrane - Antibody-dependent cell-mediated cytotoxicity
-cell destruction carried out by natural killer cells, macrophages, neutrophils and eosinophils of target cells opsonized by antibody - Neutralization
-antibody renders the antigen toxins harmless
31
Q
Antibody Classes
A
- Five classes
- IgG, IgM, IgD, IgA, and IgE - Most antibodies are IgG or IgM
- Class determined by amino acid aarrangements in heavy and light chains
- same arrangement in specific area of change
32
Q
IgM Antibody class
A
- First antibody produced against an antigen by the B cells / plasma cells
- First antibody produced by the fetus
- increased levels indicate infection in newborn - Accounts for 10 to 15% of circulating antibody
- High levels of IgM in the blood means new infection
- Very large – remains in vascular system
- Main function to activate complement system
- Can cause antigen agglutination
- Anti-A and Anti-B antibodies are the IgM type
- Function: Activate Complement
33
Q
IgD Antibody Class
A
- Second class of antigen to be released
- Not much is known about this class
- Found only in small amounts in serum and body fluids
- Has little immunologic effect on antigen
- May assist with the maturation of B cells into plasma cells
34
Q
IgE Antibody Class
A
- Third class of antibodies released
- Found in very low concentrations in plasma
- Increases with allergic reactions and parasitic infections
- causative agent for asthma, hay fever and other allergic reactions - Bind with basophils and mast cells stimulating them to release HISTAMINE
- Involved with anaphylactic reactions
35
Q
IgG Antibody Class
A
- Fourth class released
- Most Important
- Most potent
- Comprises 80% of antibody in the immune system
- when it sees it for the second time, that is when there is best response
- Secreted by Memory B Cells - only antibody that can cross the placenta
- provides immunologic protection for fetus
36
Q
Rh antibody
A
- it is an IgG antibody
- mother is negative (has antibody to Rh factor) and wants to attack a Rh positive
- child that is Rh positive will get attacked by the Rh antibodies and cause cell lysis
37
Q
IgG subgroups (4)
A
- IgG1 - protects body from (most) bacteria
- IgG2 – attacks and destroys organisms encased in a saccharide coat (rest of the bacteria)
- IgG3 – activates complement proteins (enhances phagocytosis of antigen)
- IgG4 – produces potent vasodilators (protects bronchioles)
38
Q
IgA Antibody Class
A
- Major antibody in the body fluids and mucous secreted by the mucous membranes
- Binds with antigen to immobilize it – allows mucin (main ingredient of mucous) to remove antigen-antibody complex
- Cannot activate the complement system
- Can trigger cell-mediated immune reactions
39
Q
Heaviest Immunoglobulin
A
IgM
40
Q
Highest immunoglobulin serum levels in the blood
A
IgG1 and IgG2
41
Q
Longest immunoglobulin half life
A
IgG1, IgG2, and IgG4
42
Q
Immunoglobulin good for opsinization
A
IgG1
43
Q
Immunoglobulin that stimulates our mast cells and involved in allergic rxns
A
IgE
44
Q
Immunoglobulin best for activation of compliment system
A
IgM and IgG3
45
Q
Immunoglobulin best for transport across epithelium
A
IgA
46
Q
Immunoglobulin best for transport across placenta
A
IgG1
47
Q
Immunoglobulin best for diffusion into extravascular sites
A
IgG
48
Q
Immune System
A
- Protects individual against infectious pathogens
- Must recognize and destroy harmful invaders – but do no damage to normal body tissue
- Major players - white blood cells, antibody and the complement system – variety of chemical mediators
- innate and adaptive
49
Q
Innate Immunity
A
- no control
- First line of defense – always present (skin)
- Able to respond quickly
- epithelial barriers / phagocytes / complement / natural killer cells
- Uses general recognition mechanisms to detect antigen
- Does NOT produce long term immunity to antigen
- INFLAMMATION
50
Q
Innate macrophage activity process
A
- bacterium binds to receptor on cell surface
- Engulfment into phagosome
- Degradation (phagolysosome)
- Brought back to surface and spit it out
51
Q
Adaptive Immunity
A
- Responds to specific antigen
- can be non microbial - Develops after exposure to antigen
- Slow response
- Produces very powerful response
- Lymphocytes (T & B cells) are the major players
52
Q
Characteristics of Adaptive Immunity
A
- Specificity: immune reaction specific for offending antigen
- Diversity: lymphocytes can respond to millions of antigens
- Memory: lymphocytes can remember any antigen previously encountered
- Self-regulation: lymphocytes can shut down activity after antigen is destroyed
- Self-tolerance: lymphocytes can distinguish self-tissue from non self tissue
53
Q
Recognition mechanisms of innate immunity
A
- rapid response (hours)
- invariant (doesn’t depend on invader, it will be the same way every single time)
- limited number of specificities
- constant during response (acts the same way no matter what)
- destroys foreign invader
54
Q
Recognition mechanisms of adaptive immunity
A
- slow response (days to weeks)
- variable (depends on invader)
- numerous highly selective specificities
- improve during response
- destroys foreign invader
55
Q
phases of immune response
A
- cognitive phase (first phase)
- antigen interacts with the T lymphocytes - activator phase (second phase)
- T cells respond by releasing cytokines
- cytokines stimulate proliferation of T & B cells - effector phase (third phase)
- granulocytes / macrophages / complement activated
- antigen opsonized and engulfed
56
Q
T Lymphocytes
A
- Direct immune response against protein antigen
- Responsible for the type of white cells that respond and how they respond
- T cells must recognize the antigen
T cell response to antigen is called CELL-MEDIATED IMMUNITY
57
Q
Role of T Cells
A
- Direct immune response
- Assist phagocytosis via release of cytokines that activate other phagocytic cells
- Destroy malignant cells, allogeneic cells and infected cells via lysis
- Aid B cells / plasma cells in antibody production
- Involved with delayed hypersensitivity immune reactions
- Cause some types of graft rejection in organ and tissue transplantation
- Responsible for certain types of autoimmune disorders
58
Q
T Cell Production
A
- Produced in bone marrow
- Mature in thymus
- cells trained to distinguish self-tissue from non self tissue
- Leave thymus – travel to secondary lymphatic organs
- lymph nodes
- spleen
-tonsils
59
Q
Types of T Cells
A
- Categorized by protein molecules on cell membrane (i.e. CD8+ / CD4+)
60
Q
MHC class II
A
- Extracellular antigen
- endocytosis of the antigen and breaks it down by the phagolysosome
- MHC class II binds to broken down antigen and presents it at the cell surface
- comes in contact with receptors on the CD4 T Cell
61
Q
MHC class I
A
- Intracellular antigen
- broken down by proteosome
- broken down antigen transported to ER and binds to MHC class I
- brought to surface of the cell
- comes in contact with the receptor on the CD8 cell
62
Q
Process of B cells and T cells working together
A
- Digested protein bound into a groove on the MHC molecule on surface of dendritic cell
- Dendritic cells present antigen to CD4 cells (T Helper)
- Finds a CD4 T-cell (naïve – hasn’t interacted with other antigens)
- If T-Cell Receptor (TCR) of CD4 T-Cell sees a peptide it recognizes -> Becomes active -> divides and releases cytokines
- help induce a B-cell to make antibodies - Meanwhile – antigen is also recognized by naïve B-cells with immunoglobulin molecule
- Antigen binds to immunoglobulin on B-Cell.
- ingested and digested by B-cells and react with activated T-cell to make antibodies - CD4 cell recognized antigen peptide on dendritic cell will recognize peptide present on the B-cell.
- CD4 cell activated - Activated CD4 cell with MHC-peptide on B-cells will
induce B-cells to become activated => releases antibodies
63
Q
CD40 marker
A
- B-cells have CD40 marker on cell surface
- CD4 cells (activated helper) have a ligand CD40L
- CD40 : CD40L = costimulation
- NEED CO-STIMULATION TO MAKE ANTIBODIES
