Specific Host Defenses (Immune Response) BE #4 Flashcards
innate or adaptive?
nonspecific defenses
specific defenses
innate
adaptive
innate or adaptive?
nonspecific defenses
specific defenses
innate
adaptive
Two important characteristics of the immune system are its
specificity & memory
Name 2 impt functions of dendritic cells.
- phagocytosis
2. antigen presentation
Name the 2 classes of MHC markers and id. the cell(s) they can be found on.
Class 1 - all cells
Class 2 - antigen presenting cells (APC) - dendritic cells, macrophages, B lymphocytes
Name the 2 classes of MHC markers and id. the cell(s) they can be found on.
Class 1 - all cells
Class 2 - antigen presenting cells (APC) - dendritic cells, macrophages, B lymphocytes
Two important characteristics of the immune system are its
specificity & memory
What are MHC markers?
Major Histocompatibility Complex
“self” markers; they are among the surface proteins on your own body cells & usually ignored by your immune system.
Epitope
an antigentic determinant that is the part of the antigen that is recognized by the immune system.
paratope
part of the antibody that binds to the antigenic determinant (epitope).
antigen
foreign markers that trigger an immune response
A first-time encounter with an antigen elicits a _______ immune response.
primary
Antibodies are mainly produced by what type of leukocyte?
B lymphocytes
What kind of molecule is an antibody? (protein, carb, nucleotide, or lipid)
protein
If an antibody is monomeric, how many paratopes does it have?
If an antibody is pentameric, how many paratopes does it have?
monomeric - 2
pentameric - 10
What determines the shape of the antibody?
DNA (genes)
What makes antibody specific for a particular antigen?
its structure (shape); its paratope has to fit with the epitope on the antigen
How do B cells produce the millions of different antibodies required to detect the millions of possible antigens?
The antibody shuffle: All B cells have the same genes for coding the amino acids in the antibody, but each maturing B cell shuffles the genetic code into one of millions of possible combinations, so that the sequence of amino acids in the variable region then gets shuffled. B cells can give rise to virtually unlimited chain configurations.
Define antibody titer and explain the basic procedure for determination.
Antibody titer determines how much antibody is in the blood. The blood is diluted until negative test is reached. A patient gives a positive test at any dilution down to 1:16 (1 part serum to 15 parts solvent). If a few weeks later the same patient has a titer of 1:32, this would mean she was making more antibody since it took a greater dilution to abolish the positive test.
What does Ig stand for?
immunoglobulin
gamma globulin
serum fraction containing antibody when electrophoresed
antiserum
generic term for serum (contains antibody)
serology
study of antigen-antibody reactions
What is a primary immune response?
the immune system’s first time encounter with a specific pathogen.
What are the main targets of the antibody mediated immune response?
extracellular pathogens (bacteria & viruses)
What are the main targets of the cell mediated immune response?
intracellular pathogens (bacteria & viruses)
Name 2 functions of dendritic cells in the antibody-mediated immune response.
- phagocytosis
- antigen presentation on their plasma membranes
What does APC stand for? Name 3.
Antigen Presenting Cell
- dendritic cells
- macrophages
- B lymphocytes
After phagocytosis, what is displayed on the surface of the dendritic cell?
Antigen-MHC marker complex (“wanted poster”)
Why can’t a dendritic cell just display antigen on its surface?
The cell would be recognized as foreign and phagocytized!
What induces the helper T cell to produce interleukin?
when the dendritic cell and Helper T cells bind, the dendritic cell’s interleukin stimulates the helper T cells to secrete its own interleukin.
What’s the main function of the helper T-cells in the antibody-mediated immune response?
Produce interleukin to induce the activated B cells to divide.
In the antibody-mediated response, helper T cells produce __________ which causes activated B cells to _______.
interleukin
divide
Helper T cells display _______ on their surfaces. In the antibody mediated response, these structures bind to ______________ on the surfaces of activated __________ & ____________.
complex receptors
antigen-MHC marker complexes
dendritic & activated B cells
virgin B cell
a B cell that has membrane-bound antibodies that have not ever bound to antigen
What activates or sensitizes a virgin B cell?
antigen that binds to it
Activated B cells will divide into 2 populations of cells.
- memory B cells
2. plasma cells
What induces activated B cells to divide?
Helper T cell interleukin
How are plasma cells different from activated B cells?
Activated B cells have antibody on plasma membrane.
Plasma cells secrete antibody.
Memory B cells will later be involved in a _________ immune response, which is called ________.
secondary
anamnestic
What are the 5 major functions of antibodies?
NIAAO
- neutralization
- immobilization
- agglutination
- activation of complement system
- opsonization
Once antibody has activated thee complement system (classical pathway), what can complement do?
COLA chemotaxis opsonization (act as opsonins) lyse activate inflammatory response
How are antibodies and complex receptors different?
B-lymphocytes produce antibodies
Helper T cells produce complex receptors
Antibodies bind to antigen
Receptors bind to complexes
IgG
- monomer
- largest class
- only class that can cross placenta
- all antitoxins belong in this group
- predominates in secondary immune response
IgA
- found in body secretions
- protects mucosal surfaces
- found in colostrum; protects newborns GI tract
IgM
- M for macro = 5 Y’s / pentamer when plasma cell secretes it
- in monomer form when found on surface of surface of virgin B cell & memory B cells
- extremely effective in agglutination reactions
- called “early antibody”
- produced by memory B cells
IgD
- main type of antibody displayed on the surface of B cells
- found in blood, lymph
IgE
- fixed to the surface of basophils & mast cells
- causes degranulation & release of histamine when the antibody binds to antigen
- contributes to inflammation & allergic responses
class switching
- a particular plasma cell can switch classes of antibody produced, however, all these antibodies will still have the same par atop as the original activated B cell.
What specific cell displays monomeric IgM
virgin B lymphocyte
What specific cell displays monomeric IgM and IgD?
activated B lymphocyte
What specific cell secretes pentameric IgM?
plasma cell
Explain how a memory cell will function in a secondary response.
When a memory B cell encounters the same type of antigen that initiated the primary response, it divides at once. There’s no need to wait for helper T cells to stimulate division.
What is the major lymphocyte int he cell-mediated response?
cytotoxic T cells
How do cytotoxic T cells function?
T cell complex receptors bind to complexes on the surface of infected cells, then secrete perforins that punch holes in infected cells and cause them to lyse.
Why would HIV affect both the antibody-mediated & cell-mediated immune response?
HIV attacks T cells which are involved in both antibody-mediated (helper T-cells) and cell mediated (cytotoxic T cells & helper T cells) responses.
apoptosis
programmed cell death; rids the body of unneeded cells
active immunity
a product of a person’s own immune system
- naturally acquired OR
- artificially acquired (need stick)
passive immunity
Antibodies produced elsewhere are given to a person
- naturally acquired (antibodies transferred from mother to fetus (placenta) or mother to baby through breast milk
- artificially acquired: Antibodies formed by an animal or human & administered to prevent or treat infection (Ig)
A person suffering from tetanus is given tetanus immunoglobulin (antitoxin). Explain what a person is getting when they are given this treatment and why they are getting it.
They are being given antibody against toxin. The antibody will neutralized the toxin. It helps give a “boost” to their own immune response.
What kinds of immune response is elicited by vaccination?
primary or secondary
primary
After you are vaccinated you are infected by the bacteria you were vaccinated against. What kind of immune response occurs? (primary or secondary)
secondary
What is apoptosis & why is it necessary?
it is programmed cell death. The body makes 100 million lymphocytes / day. They need to be gotten rid of.
What does ADCC stand for?
Why is it necessary to kill helminths?
Antibody-dependent cell-mediated cytotoxicity.
Helminths are too large for phagocytosis.
Classical ADCC is mediated by what type of white blood cell?
Natural Killer Cells
What type of white blood cells can kill some helminths by ADCC?
eosinophils
