immune Flashcards
Innate immunity surface defense’s
- Skin
- hair
- mucus
Innate immunity internal defenses
Mast cells + basophils (inflamatory response)
Natural killer cells
Complement system
Phagocytes: monocytes, neutrophils, macrophages
adaptive immunity cells
Inside germinal center of palantine tonsil)
T lymphocyte
antigen-presenting cells
B lymphocytes
How does inflammation work
1.Mast cells detect injury to nearby cells and release histamine initiating inflammatory response
2. histamine increases blood flow to the wound sites, brining in phagocytes and other immune cells that neutralize pathogens. the blood influx causes wound to swell, redden, and become warm and painful
steps a phagocyte uses to kill microbes
- chemotaxis
- adherence-begins to intake microbe by extending pseudopod around the microbe
- ingestion puts microbe into a vacuole and takes it into the phagocyte.
- Digestion-a lysosome with digestive enzymes binds with the vacuole
- killing-digested microbe in phagolysosome is left as a residual body(indigestible material)
how do phagocytes get to the injury
phagocytes migrate from the blood to site in a vasodilated blood channel and ‘emigrate’ out of the blood into the tissue
how does a T cell become activated
Antigen presenting cell (could be host cell 2 or infected body cell) presents the antigens
The T-cell receptor binds with the antigen-MHC complex and is then activated
What happens when an inactive helper T cell binds with an antigen MHC complex
- APC and inactive helper t cell costimulation (antigen binds to TCR on t helper cell, MHC-II binds to CD4 protein from helper t cell. APC secretes IL I, CD4 secretes IL-II)
- Step 1 activates helper t cell
- activated helper t cell undergoes clonal selection (proliferation and differentiation) creating
active helper T cells and memory helper T cells (long lived)
Types of immune defences
- Nonspecific (automatic/immediate)
- Nonspecific (innate internal)
- specific defense/adaptive/humeral immunity
nonspecific automatic/immediate immune defense types
- Barriers to entry surface defenses: skin, mucous membranes
- lysozymes: enzymes that damage bacterial cell walls. found in tears and sweat
nonspecific/innate internal defense types
- inflammatory response and fever
- protective proteins/antimicrobial proteins (mostly made in liver)
- phagocytic cells and natural killer cells (cells and proteins are involved)
Specific defense/adaptive immunity types
- Antibody mediated defense: B-lymphocytes
- Cell mediated defense: T lymphocytes
Both triggered by nonspecific, takes 5-7 days for adaptive defenses to be fully activated
Humoral immunity
Antibody mediated defense. Immunity mediated by B lymphocytes.
response is initiated when a macrophage or T lymphocyte activates a B lymphocyte. B lymphocyte make plasma cells that secrete antibodies and B memory cells
Plasma cells
Plasma cells secrete antibodies/proteins that bind and agglutinate antigens.
the antibodies are also nonspecific response to neutralize toxins/venom
Made by B lymphocytes in response to be being activated.
cell mediated immunity performed by
T cell immunity: CD4/helper t cells and CD8 cytotoxic T cell immunity.
Cytotoxic T cell function
Locate cells infected with viruses or intracellular bacteria, cancer cells, transplanted cells, lyse and destroy them.
Antibody mediated defense performed by
B lymphocytes
protective protein/antimicrobial protein function
variety of peptides that help kill microbes and attract WBC (dendritic, mast cells, phagocytes)
different types of antimicrobial proteins
2 types of antimicrobial proteins:
1. complement system proteins
2. interferons
Complement proteins
plasma proteins mostly synthesized in the liver. become active when pathogen enters the body. their actions complement/assist antibody mediated immune responses
What complement proteins do
3 major things
1. help trigger inflammatory response, causes mast cells to secrete histamine
2. can attach to microbes and marks the microbe for phagocytosis
3. form membrane attack complex/ MAC: multiple proteins that make pore/opening of cell membrane of the invader->kills the invader by cytolysis (bursts the cell
Histamine
Triggers inflammation
what forms MAC (membrane attack cells)
Complement proteins: plasma proteins mostly synthesized in the liver
MAC
Membrane attack cells
Phagocytosis
macrophages engulf microbes or neutrophils killing pathogens
what is an Interferon
Antimicrobial protein: released by cells that are infected with the virus
What do interferons do
released by cells that are infected with virus. combine with receptors of nearby cells that are not yet infected. this is a warning system telling other cells to be ready for attack.
Natural killer cells
2nd nonspecific internal defense.
Natural killer cells attack infected cells not the microbe/disease
granular leukocytes that are able to kill infected body cells by releasing granules that damage the cell membrane of the cells.
They help protect against cancer cells.
Some granules released contain perforin that perforate the membrane of the infected cell
Natural killer cells release another granule containing granzymes which induce the infected cell to die.
They are able to recognize non-self cells. markers on the outside of the cell get altered so they can be recognized as potential danger
Natural killer cells attack what
infected cells
Natural killer cells can contain what proteins
perforin, granzymes
Phagocytic cells are what line of defense
2nd nonspecific internal defense
Natural killer cells are what line of defense
2nd nonspecific internal defense
Phagocytic cells include
neutrophils
macrophages
dendritic cells
Phagocytic cells do
move to the damaged part of the body via chemotaxis and can attach to the microbe in a process called adherence. then they phagocytize the microbe (ingestion)
adherence occurs
when a phagocytic cell attaches to a microbe
Ingestion occurs
when a phagocytic cell phagocytizes a microbe
Process in which a phagocytic cell phagocytizes a microbe
phagocytic cell engulfs the microbe in a Phagosome(vesicle) which then fuses with a lysosome in the phagocytic cell to kill and break down the microbe
Macrophages and dendritic cells are derived from
monocytes and can phagocytize pathogens
Macrophages and dendritic cell function
can engulf pathogens and survive like neutrophiles.
Can release cytokines (immune hormones) which trigger monocytes to leave the blood stream into tissue to mature into macrophages
Play a role in inflammatory response and interact with specific immune responses
when does a monocyte become a macrophage
when it leaves the blood stream and enters tissue
cytokines are considered
immune hormones
what can engulf pathogens and survive
phagocytic cells:
neutrophils
dendritic cells
macrophages
What attracts phagocytes to wounds
histamines and mast cells. phagocytes respond to inflammation
Outward signs of inflammation
- redness
- heat
- swelling
- pain
what happens during inflammation
Chemical signals like histamine will induce capillary dilation->increases blood flow to the infected area
Increased blood flow makes the area red and warm
proteins and fluids leave capillary into interstitial tissue causing inflammation
neutrophils and monocytes(become macrophages) can also leave capillaries.
Sometimes inflammation triggers a fever. Fever triggered by the brain. Certain phagocytic cells release cytokines called pyrogens (example interleukin 2) cytokines tell hypothalamus to make the body a higher temp
how is fever produced
Fever triggered by the brain. Certain phagocytic cells release cytokines called pyrogens (example interleukin 2) cytokines tell hypothalamus to make the body a higher temp
antigens
any foreign substance that stimulates a reaction by the immune system.
antigens have immunogenicity: ability to stimulate an immune response
Antigens have reactivity: ability to react with antibodies or cells
immunogenicity
immunogenicity: ability to stimulate an immune response
