Immunology: Antigens, T/B Cell Antigen Receptors, Clonal Expansion & T Cell and Their Functions - Dr. Hudig Flashcards
T or F, measles are preventable with adaptive immunity?
true
What is this:
occurs in 1/1000 infected children.
10% mortality w/ encephalitis
preventable with adaptive immunity
acute measles encephalitis
T or F, the vaccine for measles contains live attenuated virus
T
What are the four types of pathogens?
bacteria
yeast and fungi
viruses
parasites
Is bacteria intracellular or extracellular?
can be both
Is yeast intracellular or extracellular?
extracellular
Are viruses intracellular or extracellular?
intracellular
Are parasites intracellular or extracellular?
can be both
T or F, adaptive immune mechanims differ for different pathogens
T
Which is worse, an extracellular pathogen or intracellular pathogen?
intracellular because its harder to kill
How do you kill an intracellular bacteria?
With TH1 which will emit interferon gamma that signals to macrophages to kill the cell
How do you kill extracellular bacteria?
neutrophils bind to antibodies n bacteria and kill it or use kuppfer cells (macrophages) in the liver
What are some common intracellular bacteria?
listeria, salmonella and shigella
(blank) is a ‘type II’ interferon secreted by T helper cells when they are activated after recognizing foreign antigens.
Interferon-gamma
Mycobacterium tuberculae cause (blank) . M. tuberculae live and replicate (blank) the macrophages that ingest them.
tuberculosis
inside
What are the antibodies that bind to yeast?
opsonins
How do you kill yeast and fungi?
antibody opsonizes the yeast/fungi and then are killed by neutrophils
How do you kill a virus?
CD8 cytotoxic T cells, infected cell dues and immature virions inactivate
Can antibodies help w/ killing viruses?
it depends on the virus, some antibodies can prevent viral entry into a persons cells
Where do you find plasmodium?
inside RBCs in a stage of malaria
How does your body react to Ascaris?
IgE and mast cellresponse so eosinophils will help out
What causes river blindness?
Onchocerca volvulus
What 2 cell types control viruses in innate immunity compared to adaptive immunity?
innate-> NK cells
adaptive-> Cytotoxic T (killer CD8 positive) lymphocytes
Describe adaptive immunity
specific, inducible, takes a long time (~ 5 days), involves T and B lymphocytes w/ specific receptor, Utilizes T and B receptors that are not directly genome encoded, generates memory, lasts the lifetime of the immune person, eliminates infections faster than innate immunity.
T or F, adaptive immunity eliminates infections faster than innate immunity?
T
What is a Tcell?
Require differentiation in the
thymus. Effectors of cell-mediated immunity.
What is a B cell?
differentiate in bone marrow. Secrete antibody proteins after encounter with their related antigen
What is an antigen?
foreign structures recognized by T cells, by B cells and by antibodies
What is an epitope?
the structures within antigens that bind to B and T cell receptors for antigens
What is impetigo?
a skin infection caused by staph and strept which colonizes skin damaged by a previous lesion.
who does impetigo usually attack and why is it worrisome?
children in warm, humid, dirty environments, it is very contagious
(blank) is a foreign substance that is specifically recognized by the immune system
antigen
T cell antigens are almost always (blank)
peptides from foreign proteins
HOw do antibodies recognize antigens?
specific protein, carbs or lipid sequences.
HOw do antibodies recognize strep pyogenes?
via its M proteins
How do T cells recognize antigens?
foreign peptides in MHC II for CD4 T helpers and foreign peptides in MHC I for CD8 T killers
What is a T cell antigen?
peptides from foreign proteins bind to MHC proteins and are recognzied by the T cell receptors
What is a B cell antigen?
any foreign substance that can bind to the immunoglobulin B cell receptor for antigen and to antibodies
T cell receptors have what property that allows them to bind to a foreign peptide at the same time as it binds to MHC?
dual recognition
TCRs always have how many chains?
2 chains
TCR have two chains, what can these chains be made up of?
either alpha and beta
or
gamme and delta
What kind of CD number to cytotoxic T lymphocytes have?
CD8
What kind of CD number do T helpers and other T cells have?
CD4
In circulation T cells are either (blank) positive, (blank) positive or neither
4
8
What does T helper cells and other T cells that arent CTLs have as co-receptor that will bind MHC II?
CD4
What do CTLs have that act as a co receptor to bind MHC I?
CD8
What do you find on ALL T cells? Why is this important to know?
CD3
cuz if something has CD3 on it, you automatically know it is a T cell AND it is a signalling molecule
What molecules found on the T cells are used to initiate signaling to the cell that an antigen has bound?
CD8, CD4, CD3
Can a T cell receptor recognize an antigen that is not hooked up to a MHC?
no it cannot
(blank) lymphocytes must recognize antigens and divide before they can provide the help required for T and B cell responses.
T cells
How long does it take for a T cell to divide?
6 hours
Explain how a pathogen comes in and then you end up with T cell proliferation
Pathogen comes in and gets presented by the antigen presenting cell. This APC then binds to its corresponding T cell recepetor. Clonal proliferation occurs. After 5 days there are enough clones with the ability to secrete cytokins and IL2 that the adaptive immunity can kick in.
What is IL-2?
it is a growth factor for all lymphocytes
How do B cells respond to an antigen?
B cells have an IgM single chain receptor that will bind an antigen if a T helper cell is present. The b cell then starts dividing and the clones differentiate and become plasma cells which secrete antibodies. They then move to the bone marrow and sit and secrete. A few cells will become memory cells and run around the body looking out for future attacks.
Why kinds of cytokines will b cells produce?
IL-2 , then once matured also IL 4
What kind of receptors do B cells have>
Immunoglobulin monomer (IgM)
How many chains do you need to hold an antigen?
2!!! in T and B cells
Describe the structure of the receptor of a B cell (IgM)
2 identical light chains and 2 identical heavy chains held together by disulfide bonds that form a hinge. There are three complementarity determing regions (CDRs) that hold the antigen to the receptor.
Constant regions of (blank) chains determine Ig Class and subclass
H
Light chains of human Ig’s are either (blank) or (blank)
kappa or lambda
Describe the structure of an antibody
Ther is a antigen binding region and a crystallized fraction. The crystalized fraction binds to the cellular receptors of leukocytes.
Why are Fab and F(ab’)2 antibodies often used for diagnostic purposes?
Because it lacks an Fc region which means it wont bind to cellular receptors .
How do neutrophils recognize and antigen and eat it up?
via the Fc region of an antibody
How do you break the antigen binding region from the Fc region of the antibody and create 2 monomers?
How do you create 1 dimer?
via Papain protease
via pepsin protease
Antigens (Ag’s) for B cells can be (blank) or (blank) determinans of foreign proteins or even (blank) created by proteolysis of self proteins.
conformational
linear
neoantigens
(blank) may promoto autoimmunity if self proteins are cleaved
neoantigens.
Can conformational determinant have their determinant lost by denaturation?
yes
Can linear determinants have their determinant lost by denaturation?
no
How do you get a neoantigenic determinant?
you take a self protein and splice into something that looks foreign and then your body things its a bad thing
Specific immune responses take (blank), then last
time
How come you have a lag in immune response when you get a shot and why are boosters awesome?
T helpers have to divide a lot before stimulating B cells. B cells have to divide a lot before making antibodies.
Boosters are awesome because it allows your immune system to make more antibodies to it.
how come when you get a vaccine you dont maintain your levels of IgM?
because IgM is an initial exposure immunoglobulin from B cells which eventually will diminish TO ZERO and instead IgG will be made and be left over to provide immunity.
Diverse T and B cells, each with a different and specific (blank)
receptor
(blank) lymphocytes make cytokines, kill or produce antibodies
(blank) lymphocytes persist
Effector
Memory
