Chapter 45: Immune system Flashcards
What are the 3 lines of defense mammals have?
physical barriers, innate immune system, and adaptive immune system
How does the innate differ from the adaptive immune system?
innate is faster (immediate) , creates a nonspecific response, and has no memory, occurs in all animals
adaptive immunity is vertebrates only
Origin of lymphocytes?
form in bone marrow and then migrate to thymus
Which WBC are granulocytes?
basophil and eosinophil
Which WBC are phagocytes?
neutrophils, monocytes, and lymphocytes
Which cells are involved in innate immunity?
basophil, eosinophil, neutrophil, mast cells, and natural killer cells
Which cells are intermediates of innate immunity and adaptive immunity?
macrophages and dendritic cells
Which cells are involved in adaptive immunity?
B cells, T cells, cytokines, and cytotoxic molecules
How long does they body take to generate and effective response to a pathogen?
7-10 days
What are toll-like receptors?
surface receptors and internal receptors which recognize PAMS (pathogen-associated molecular patterns)
What are defensins?
antimicrobial peptides that disrupt plasma membranes and inhibit intracellular functions of a pathogen
What are the 4 components of inflammation?
1) calor = heat
2) rubor = redness
3) tumor = swelling
4) dolor = pain
What are cytokines?
secreted by activated macrophages and bind to host cells to trigger a response. make the blood vessel wall stickier
What are chemokines?
activated macrophages secrete this to attract neutrophils and monocytes
What do monocytes differentiate into?
macrophages
What are pyrogens?
macrophages release this to stimulate the hypothalamus to release locally-acting prostaglandins to create a fever.
What is the complement system?
30+ plasma proteins that circulate in blood and ISF. Some assemble into membrane attack complexes which create pores in bacteria cells where water flows and causes the bacteria to lyse
Can the innate immune detect viruses?
nope, bc it’s in the the host cell
Which two cells do the innate immune system use?
interferon and natural killer cells
What are interferons?
cytokines that tell neighboring cells that it has been infected and to pull their receptors. The host cells inhibits protein synthesis and prepares to die:(
How do natural killer cells work?
perforin creates holes in target cells which allow granzymes in that have enzyme bombs to kill target cell in a controlled manner.
What are MHCs?
major histocompatibility complex proteins
high levels mean self cell, MHC 1 is a self marker
What are the 2 sub categories of adaptive immunity?
humoral (B cell immunity) and cellular (t cell immunity)
What are the 4 key characteristics of the adaptive immune response?
1) specificity
2) diversity
3) memory
4) self-nonself recognition
How does anitbody-mediated immunity work?
B-cell derivatives called plasma cells secrete antibodies which tag antigens
How does cell-mediated immunity work?
a certain t cell is activated and with other cells, directly kills foreign cells
What are b cells?
from bone marrow and carries in blood to capillary beds to serve lymphatic system, 2 binding sites
What are t cells?
from bone marrow and carried in blood to thymus, 1 binding site
What are the 2 kinds of t cells?
helper t cells and cytotoxic t cells
What are the 4 steps of the adaptive immune response?
1) Antigen encounter and recognition: lymphocytes encounter and recognize an antigen
2) Lymphocyte activation: lymphocytes are activated by binding to the antigen and divide to produce clones
3) Antigen clearance: large clones of activated lymphocytes clear the antigen from the body
4) Development of immunological memory: memory cells circulate in blood and lymph, prepared for a rapid response
Structure of an antigen recognition site?
heavy and light chains, the heave chain has constant regions and the light chain has a variable region. held together by disulfide bonds
What are epitopes (antigenic determinants)?
signals on the antigens surface
What happens in the 1st step in the anitbody-mediate immune response?
engulfment of bacterium,
dendrite cell engulfs bacteria by phagocytosis
What happens in the 2nd step in the anitbody-mediate immune response?
degradation of bacterium and release of antigens,
dendritic cells migrates to lymph node, in the dendritic cell the vessel with the bacterium fuses with a lysosome that degrades the bacterium’s protein into short peptides = anitgens
What happens in the 3rd step in the anitbody-mediate immune response?
presentation of antigens on dendritic cell surface
antigens bind to MHC2s which are displayed on the surface and converts the cells into an antigen-presenting cell (APC)
What happens in the 4th step in the anitbody-mediate immune response?
interaction of antigen-presenting cell with lymphocyte
APC presents antigen to lymphocyte (CD4+ t cell) and links together
What happens in the 5th step in the anitbody-mediate immune response?
activation of t cell
bound APC secretes interleukin (cytokine) that activtes the associated t cell
What happens in the 6th step in the anitbody-mediate immune response?
production of helper t cells
activated t cells secrete other interleukins to stimulate clonal expansion = creation of more activated CD4+ T cells
clonal cells differentiate into helper t cells = effector t cell which is involved in effecting the specific immune response to the antigen
What happens in the 7th step in the anitbody-mediate immune response?
presentation of antigens on b cell surface
antibodies are produced in activated b cells. activated b cells present antigen on its surface to link with a helper t cell. bacterium plus b-cell receptor is taken into the dendritic cell
What happens in the 8th step in the anitbody-mediate immune response?
interaction of b cell with helper t cell
a b cell find a t cell displaying the same antigen and become tightly linked, usually in lymph node spleen
What happens in the 9th step in the anitbody-mediate immune response?
activation of b cell
linkage stimulates helper t cells to secrete interleukins that activate b cell and stimulate the b cell to proliferate = creates clones
What happens in the 10th step in the anitbody-mediate immune response?
production of plasma cells and memory b cells
cloned cells differentiate into short-lived plasma cells which secrete antibody. also differentiate into memory b cells which are long-lived cells which prepare for a more rapid response if antigen is encountered later on
What is clonal selection?
process where a particular lymphocyte is specifically selected for cloning when it recognizes a particular foreign antigen
What class of proteins do antibodies belong to?
immunoglobulins (Ig)
What type of chains are in an antibody?
2 heavy identical chains
2 light identical chains
What is the structure of each chain on an antibody?
each has a constant region and variable region
What determines the antibody class?
constant regions of the heavy chains in the tail part of the y shaped structure
What are the 5 different classes of antibodies
IgM, IgG, IgA, IgE, IgD
What do IgM’s do?
large, remains bound to cells that make it, can find 10 epitopes
What do IgG’s do?
most abundant, produced in large amounts when exposed to an antigen for the second time, small, movable
What do IgA’s do?
blocks attachment to body surfaces, in breast milk
What do IgE’s do?
secreted by plasma cells of the skin and linings of the gastrointestinal and respiratory
tract binds to basophils and mast cells,
triggering release of histamine
used in parasites and allergies
What do IgD’s do?
occurs with IgM as a receptor on the surfaces of B cells, its function is uncertain
What is neutralization?
toxins neutralized by antibodies which bind to toxin molecules and prevent them from carrying out their damaging action
What is agglutination?
clumping of bacteria by the antibodies and prevents further infection
How does the complement system work in bacteria versus viruses?
insert and form pores to make bacteria lyse
insert into membranes of enveloped viruses which prevent the virus from infecting cells
How are monoclonal antibodies formed?
1) test animal is infected and develops and immune response
2) activated B cells are extracted and fused with cancerous cells
3) creates antibodies
What types of immunity are there?
passive and active
What ways can you acquire immunity?
natural or artificial
What cells are involved in cell-mediated immunity?
cytotoxic t cells
What do cytotoxic t cells kill?
host cells infected by pathogens (viral), cancer cells that have an altered MHC 1
What are the 5 steps in the cell-mediated immune response?
1) presentation of antigens on the cell surface
2) activation of the t cell
3) production of cytotoxic t cells
4) attack of infected cell by cytotoxic t cell
5) destruction of infected cell
MHC 1 binds to what CD? MHC 2?
MHC 1 binds to CD8
MHC 2 binds to CD4
What do activated CD8 T cells differentiate into?
cytotoxic t cells and memory cytotoxic t cells
What is type 1 diabetes a reaction to?
against the pancreatic beta cells that produce insulin
What is lupus a reaction to?
antibody production against blood cells, platelets, mitochondria and proteins associated with DNA
What is rheumatoid arthritis?
attacks connective tissues in the joints which causes pain and inflammation
What is Multiple sclerosis?
attacks myelin sheaths of neurons
What is a viruses latent state?
stage where they cannot be isolated from the infected organisms and identified
What are allergies?
increases of IgE antibodies that find to receptors on mast cells in connective tissue and basophils. This causes the secretion on histamine which causes inflammation
