Unit 3 Lecture 20 Flashcards
What are the two types of immunity in the body?
Adaptive and innate immunity
Define innate immunity
The body’s nonspecific way to fight off foreign invasions
*uses first lines of defense
Define adaptive immunty
A more specific way the body fights off foreign invasions
How can you differentiate adaptive immunity from innate immunity?
- Specificity for antigens and tolerance for proteins
- Memory for past antigens
What are the two types of adaptive immunity?
- Cell mediated immunity
2. Antibody mediated immunity
Antibody mediated immunity involves what type of cells?
Helper T cell CD4
and
B cells
Antibody mediated immunity involved what type of receptors?
T cell receptors and B cell receptors
What type of cells and receptors are involved in cell mediated immunity?
Cytotoxic T cell receptors on T cells
What protein presents foreign antigens in antibody mediated immunity?
MHC II protein
Antibody mediated immunity defends the body from specific pathogens from where?
outside (extracellular)
How is antibody mediated immunity tolerant?
By not recognizing self-antigen presented by MHC II proteins, it’s tolerant of our own proteins, nucleic acids, lipids, and polysaccharides
What is the specific role of T cell receptors during antibody mediated immunity?
Recognition of foreign antigens
- meaning T cells receptors will always have the foreign antigen on it
What is the specific role of B cell receptors during antibody mediated immunity?
- Presenting MHC II protein
- binding antigens
- endocytosis
What type of T helper cell is involved during antibody mediated immunity?
Effector Helper T cells (Th* cell)
How is each receptor different?
genetic recombination
What part of the receptor connects to the foreign antigen on the TCR
variable region
AGAIN, how are B cell receptors tolerant?
By NOT binding to SELF-ANTIGEN, BCRs are tolerant of own proteins, nucleic acids, lipids and polysaccharides
What are B cells only specific for
foreign antigens bc of selection
Where do B cells originate and mature?
Red bone marrow
What condition allows B cells to survive selection?
Negative selection to self-proteins
What happens when there is positive selection to B cell’s self-proteins?
Death of B cell
Where does the mature B cell go after negative selection to self-proteins?
Lymphatic tissue
What happens to the B cell with co-stimulation after helper T cell recognizes the antigen?
Activation of B cell -> differentiation/ clones of B cells
What are the steps of antibody mediated immunity?
- Antigen presentation by B cell
- Antigen recognition by Helper T cell
- Activation of B cell (co-stimulation by Th* cell)
- Proliferation (copy) and differentiation (child) of B cell
- Action
How do B cells present their antigen?
B cells bind to free antigen in lymph or interstitial fluid and present it
How is MHC II presented on B cell?
Brought into cell via endocytosis then presented on cell
What happens during antigen recognition?
Th* cell receptor FITS with MHC II protein receptor on B cell, it’s seen as a FOREIGN VIRUS
How are B cells activated?
When the Th* cell recognizes a foreign antigen, Helper T cell releases co-stimulators (CYTOKINES) ie. interleukins to activate B cell
What happens to activated B cells?
Proliferate (clone) - Memory B cell
different - Plasma cells
What do Plasma cells do?
Secrete antibodies w the exact same antigen on original B cell
What happens to effector (plasma) B cells and their antibodies?
effector B cells (plasma) do not leave the lymphatic system!!!!!
- antibodies leave lymphatic system and circulate body
What are the floating B* cell antibodies looking for?
the same unprocessed antigen
What do B* cell antibodies do to the foreign antigen they find?
Inactivate it and tag it for destruction
What are the different defense mechanisms antibodies use against foreign antigens?
- Neutralization
- Immobilization
- Agglutination
- Precipitation
- Complement fixation
- Enhancement of phagocytosis
What is neutralization
inactivates antigens by blocking its toxins or preventing its attachment to body cells
What is immobilization
inactivates movement of bacteria by attacking cilia/ flagella
What is agglutination and precipitation
inactivates antigen by clumping and breaking up antigens
What does complement activation do to the antigen?
fixes and activates it
What is another name for antibodies?
immunoglobulins
What are antibodies structure made up of?
2 parallel protein chains
-Light and Heavy chains
What are the light and heavy chains on antibodies?
Heavy - single stem part of Y
Light - two branches of Y
What is important about the heavy chain?
it’s the “constant region”
What is important about the light region?
It’s the “variable region” where antigens bind to
How many classes of antibodies are there and what are they based off of?
5, constant regions
What are the major types of antibodies/ immunoglobulins?
IgG, IgE, IgD, IgM, and IgA
G,A,M,D,E
grandma and mom do everything
What immunoglobulin accounts for the most?
IgG- 75%
What is unique about IgG?
it’s the only antibody that crosses the placenta
What do all antibodies do?
all are passed in breast milk
What is antibody titer?
a test that measures the amount of antibodies within blood
What is the primary response during an antibody titer?
IgM and IgG levels have little peaks between 7-10 days after first interacting with the antigen
What still remains in the blood after antibody/ immunoglobulin levels go back down?
Memory B cells
What happens during the secondary response of antibody titer?
re-exposure to the same foreign antigen
What is the result of the secondary response of antibody titer?
IgG increases exponentially a LOT bc memory cells proliferated (copied) after the first exposure
