CH 15 - immune system Flashcards
What are the 2 types of immune systems?
Innate (nonspecific) immunity
Adaptive (specific) immunity
What are the 3 main parts of the innate immune system?
Physical barriers (skin/mucous membranes)
High acidity (stomach/fevers)
Antimicrobial peptides and interferon (wbc)
What is activation of innate immunity?
Cells distinguish “self” from “nonself” using pathogen-associated molecular patterns (PAMPs) unique to the pathogens.
What are lipopolysaccharides found in/used for?
found in the envelop of Gram-negative bacteria
What are peptidoglycans found in/used for?
The cell walls of Gram-positive bacteria
How does innate immunity work?
Secrete chemokines to recruit more immune cells
Secrete cytokines to promote aspects of innate and adaptive responses
What is:
~ Located in the cytoplasm
~ Used to recognize intracellular molecules from bacteria
~ Activate the production of cytokines
~ Can lead to programmed cell death of infected cells
NOD-like receptors
What is the job, make, and promotion of the complement system?
Integrates innate and adaptive immune responses.
Consists of proteins in the plasma and other body fluids that become activated when antibodies bind to antigens.
Complement proteins promote phagocytosis, lysis of target cells, and local inflammation.
In innate immunity, what are the 3 signs of local inflammation with no infection?
Tissue damage occurs that causes necrosis.
Immune system exposed to DAMPs – danger-associated molecular patterns, after cell injury.
Stimulates innate immune responses and inflammation.
What is the job of toll-like receptors?
Only let in recognizable pathogens
What are the types of phagocytic cells?
Neutrophils
Mononuclear phagocytic cells
When does neutrophils arrive (and to where)?
The first to arrive at an infection.
When does mononuclear phagocytic cells arrive (and to where)?
(monocytes in the blood and macrophages and dendritic cells in the tissues) arrive after the neutrophils
What are the 6 steps of phagocytosis in tissues?
Neutrophils and monocytes undergo extravasation (diapedeses): squeeze through gaps in post-capillary venule walls to enter tissue
Brought to the site from chemotaxis by cytokines/chemokines
The pathogen becomes engulfed by pseudopods.
The vacuole containing the pathogen fuses with a lysosome.
The pathogen is digested.
Lysosomal enzymes may be released before fusion is complete, killing the cell, and contributing to local inflammation.
What regulates/produces fever?
Regulated by the preoptic area of the hypothalamus that acts as a thermostat.
Prostaglandin (PGE2) acts as a paracrine regulator to produce fever.
Why is too high of a fever bad?
Fall in plasma iron concentration.
Inhibits bacterial activity.
Increased activity of neutrophils and more interferon production.
What are interferons?
Antiviral polypeptides produced by infected cells that cause non-specific, short-term resistance to viral infection
What is adaptive immunity?
The acquired ability to defend against specific pathogens after exposure to these pathogens
Read me :D
(do it and mark this as a 3 or 4)
Relax your posture
Take a deep breath
Unclench your jaw
Go drink water
You got this!
What are antigens and what are their jobs?
Foreign antigens illicit an immune response. The immune system can distinguish “self” from “nonself.” (bad)
What are T-Lymphocytes?
Lymphocytes that seed the thymus become T lymphocytes.
These then seed the blood, lymph nodes, and spleen.
T lymph. attack host cells that are infected with a virus or fungus (and cancer)
What is cell-mediated immunity?
T-lymphocytes which must be in close proximity to the victim cell in order to destroy it.
What are B-Lymphocytes?
Lymphocytes that come directly from bone marrow to seed other organs (not the thymus) are called B lymphocytes.
They combat bacterial and some viral infections.
What is humoral immunity or antibody-mediated immunity?
B-lymphocytes which secrete antibodies into blood and lymph so can be far from the infection.
What are the secondary lymphanoid organs?
Lymph nodes
Spleen
Tonsils
Peyer’s patches (in mucosa of intestines)
What are the organs that filter for pathogens?
Which filter what part of the body?
The spleen filters blood for pathogens.
Other organs filter lymph for pathogens.
What does Pyrogens release?
PGE2 release for fever (Prostaglandin E 2)
what are the evil things that causes immune reactions?
ANTIGENS!! >:(
What do antibodies do to the evil thing (and what is the evil thing?)
Antibodies bind to their specific antigen to destroy it
What are the primary lymphoid organs?
Bone marrow
Thymus
Tips for remembering the lymphocytes (pls read fully w/o skimming. I promise its helpful)
Where are they from:
B cells are found in the Bone marrow
T cells are found in the Thymus
What do they do?
B cells combat Bacterial and some viral infections.
T cells attack host cells that have become infected with a virus or fungus, transplanted human cells, and cancer cells.
Which creates antibodies?
B cells (antiBody)
What immunities are they?
B: humoral immunity or antibody-mediated immunity (B is the only one w/ antibody)
T: cell-mediated immunity (T attacks cells directly)
What is the process of B lymphocytes?
Exposure to the specific antigen activates a B lymphocyte.
Enters the germinal center of a secondary lymphoid organ.
Undergo multiple cell divisions (cloning). (thousands a sec)
How do B cells help in the long run?
Some become memory cells, which are used in a later infection by the same pathogen
What happens to the majority of B cells?
A few become memory cells (minority)
Others become plasma cells, which produce 2,000 antibodies/second (majority)
What are the 5 types of immunoglobin?
IgG
IgA
IgM
IgE
IgD
(gamed)
Here’s some antibody structure info you’ll have to memorize bc I have no idea how to formulate it into a question (copy paste from slide 29)
a. Y-shaped protein
2 long, heavy (H) chains joined by 2 shorter, light (L) chains
The bottom (Fc) is constant across different antibodies, whereas the top (Fab) varies and allows antigen specificity.
What do killer (cytotoxic) T Lymphocytes
do? (like how do they work?)
Destroy cells with foreign entities
Cell mediated destruction
Secrete perforins and granzymes
What do helper T Lymphocytes do?
Assist B lymphocytes to become plasma
Enhances cytoxic (killer) T cells
What do regulatory T Lymphocytes do?
Inhibit B lymph. and cytotoxic T cells
What are the 3 types of T Lymphocytes?
Killer (cytotoxic)
Helper
Regulatory
What is:
~ Originate in the bone marrow and migrates to tissues where pathogens enter
~ Helps T cells see the enemy
~ Secrete cytokines to attract T lymph. in secondary organs
Dendritic cells
What is:
~ On all body cells except mature RBC
~ Called human leukocyte antigens
Major histocompatibility complex (MHC)
What are the differences between class 1 and class 2 major histocompatibility complexes?
Class 1:
Made by all cells except RBC
“Self antigens”
Keeps foreign antigens from activating cytotoxic T cells
Class 2:
Antigen presenting cells
Foreign antigens and class 2 get presented together to helper T lymph.
What are the 2 t lymphocyte cell coreceptors (and what do they come from)?
Killer T cells have CD8 for MHC-1
Helper T cells have CD4 for MHC-2
What is igG?
main form of antibodies in circulation: production increased after immunization; secreted during secondary response
What is igA?
Main antibody type in external secretions, such as saliva and mother’s milk
What is igE?
Responsible for allergic symptoms in immediate hypersensitivity reactions
What is igM?
Function as antigen receptors on lymphocyte surface prior to immunization; secreted during primary response
What is igD?
Function to antigen receptors on lymphocyte surface prior to immunization; other functions unknown
What does a lack of regulatory T lymphocytes do?
Causes autoimmune diseases and allergies
What are the 7 steps in the process of T cells responding to a virus?
~ Virus phagocytosed by macrophages or dendritic cells
~ Viral foreign antigens (FA) moved to surface of presenter cell
~ FA form a complex with MHC-2
~ Macrophage secretes IL-1(interleukin-1) to stimulate cell division and proliferation of T cells
~ IL-1 stimulate helper T cell mitosis
~ Helper T cells promote macrophage activity
~ IL-2 activates cytoxic T cell activity
B cell response to T cells and antigen presenting cells?
Activated helper T cells promote humoral response of B cells by binding to foreign antigens and MHC-2s
This stimulates mitosis of B cells, conversion to plasma cells, production of antibodies and memory B cells.
Allows class-switched antibody formation
What are the steps of T cell destruction?
~ Activated T cells must be destroyed after the infection is over
~ Active T cells produce a surface receptor called FAS
~ Binding of FAS to FAS ligand induces apoptosis.
In active immunity, what happens with the primary response?
After infection, it takes 5 to 10 days before antibodies are detected in the blood.
In active immunity, what happens with the secondary response?
Later exposure to the same infection results in maximum antibody production in less than 2 hours.
What is clonal selection theory? (copy paste)
(Explains secondary response)
A person inherits lymphocytes specific to almost every pathogen, but there are few of each type.
When exposed to foreign antigens, immune cells respond by making many copies of themselves.
Germinal centers in secondary lymphoid organs develop to produce the clones
Proliferating B cells undergo somatic hypermutation which generates a diversity of antibodies with different antigen-binding receptors
Those with the strongest affinity for the antigen are selected for greater cell division, while the others undergo apoptosis
The selected B cells continue this process until those with the strongest affinity for the antigen survive to form memory cells and plasma cells that produce high-affinity antibodies for a more effective secondary response
What is the relation between secondary response and active immunity?
a. Development of the secondary response provides active immunity
b. Requires prior exposure to the antigen and then protects the body from future infections
c. Active immunity is also used to make vaccines.
What are vaccines/how do they work? (copy paste)
Stimulate a primary response and active immunity without making the person sick.
What is passive immunity?
Passing of antibodies from one individual to another; person does not make their own antibodies or memory cells.
Provides temporary protection
What helpful thing is inside vaccines?
Adjuvants
What are adjuvants?
Molecules that boost adaptive immune response when delivered with the vaccine antigens
Which ig is most abundant in the blood?
igG
What is the cytotoxic T-cell molecule?
CD8
What is the helper T-cell molecule?
CD4
MHC-1 is made by which cells?
all but RBC
What is a MHC-2 cell?
Antigen presenting cells
Which response is for vaccines?
Active
Which response is mothers’ milk to baby?
Passive
Which response is a snake bite with antivenom?
Passive
Which response is getting sick to make an immune response?
Active
If you get a vaccine, but someone else gets you sick, what response is that?
Active
What are the 2 proteins secreted in cell mediated immunity?
Perforins
Granzymes
Which cell mediated immunity protein creates a large pore in a cell?
Perforins
Which cell mediated immunity protein triggers apoptosis in the cell through action of caspase enzymes?
Granzymes
What are the 3 ways to make a vaccine?
Use a killed virus
Use a live virus that can’t replicate or infect target tissues
Use a genetically engineered recombinant virus
primary or secondary:
Which will a person get sick with?
Primary
Primary or secondary:
Which will keep a person from getting sick?
Secondary
