Immunology week 8 Flashcards
Week 8 repeats Week 7
Slides 0-6 wk8 are slides 32-36 wk 7
(Cellular Immune Response III)
**Week 8 repeats Another week that must be in physical cards as I can’t find it in digitial cards so I am redoing it so you have it Humoral Immune Response
Humoral
Immune
Response
Antibodies
What are AB?
AB- are important for eliminating AG
○ They are the only defense mechanism against microbes in the lumen of mucosal organs
and in the fetus and newborns
Humoral
Immune
Response
Antibodies
● Why are AB important?
(5)
Why are AB important?
○ Neutralization of microbes
○ Opsonization and phagocytosis of microbes
○ AB dependent cellular cytotoxicity
○ Phagocytosis of microbes opsonized with complement fragments
■ Remember C3B and C5B are important for this ;)
○ Complement activation
■ Inflammation
■ Lysis of microbes
Humoral
Immune
Response
Antibodies
What do AB block? How? what is an example?
AB against microbes and toxins BLOCK the binding of these microbes to
cellular receptors
○ Ex: tetanus vax= will produce memory antitoxin cells so if the body ever comes in contact
with that toxin it will already have memory cells to induce an IR
Humoral
Immune
Response
Antibodies
What is Primary IR?
What is Secondary IR?
What is DC1?
What is DC2?
● Primary IR= the first time that an AG has entered the body
○ Effector(80%) and memory cells(20%) are produced
● Secondary IR= the AG has already entered the body before so memory
cells have already been produced
● DC1- trap AG endogenous cells produce IL12 and stimulate t helper cells
● DC2- IL1 and stimulate type 2 t helper cells
Humoral
Immune
Response
Antibodies
Primary IR
During primary IR, what 2 types of cells are produced, how many? (% of each)
○ Effector(80%) and memory cells(20%) are produced
Humoral
Immune
Response
Antibodies
DC1 traps what?
produces what?
stimulates what?
DC1- trap AG endogenous cells produce IL12 and stimulate t helper cells
Humoral
Immune
Response
Antibodies
DC2
produces what?
stimulates what?
DC2- IL1 and stimulate type 2 t helper cells
Humoral
Immune
Response
Antibodies
what is opsonization?
what are some things that can increase opsonization?
● Opsonization
○ Increases phagocytosis by 10 fold
○ What are some things that can increase opsonization?
● FCyRI(CD64) receptor (Ig1 and IG3)- macs, neutrophils, & NK cells
● Fcdelta(IgE)- eosinophils
graphs on slide 12
Complement system
is it innate or adaptive IR?
Both innate and adaptive IR
Complement system
what are the 3 pathways?
classical
lectin
alternative
compliment system
what is the final result?
MAC
complement system
what are important by products that aid in opsonization?
C3B and C5B are important by products that aid in opsonization
Week 8 is a repeat of Week 4
slides 14-15 wk 8 are slides 7-11 wk 4
Compliment sytem
Antibodies
Anitbodies–when?
exogenous Ag–destroyed by anitbodies–produced by B cells
Antibodies
Anitbodies–when?
exogenous Ag–destroyed by anitbodies–produced by B cells
Name the 4 functions and describe:
1-Against Bacteria
neutralisation of toxins or enzymes
killing–compliment–classical pathway
ADCC–Fcy receptor(IgG and Fc8 (IgE)
2-Against viruses
virlon–complement or phagosytosis
3-Against parasites
Th2–IgE+epsinophils
4-Against Tumors**
Not is solid ancers
lymphosarcomas-compliment
lymphosarcomas=50%of cells destoyed by compliment**
BCR
How many chains, what types?
Contains 4 peptide chains (2 heavy and 2 light)
BCR
how many and what kind of binding sites?
● 2 AG binding sites
○ Is this true for TCR too??
BCR
T dependent
explain
● T dependent
○ Typically “better”
○ Strong IR and produces memory cells
○ Cells will undergo class switching so IgM-> IgG and IgA
BCR
T independent
explain
T independent
○ Really only good for AG with repeating polymers
■ E.coli, salmonella, etc
BCR
BCR has two roles, what are they
BCR has two roles:
○ Binding to the AG results in biochem signals-> activation
○ BCR internalized the bound AG (protein) into peptides that may be presented by class 2
MHC on the b cell surface for recognition by t helper cells
**Structure of Tcell and Bcell receptors p. 17
Costimulation of B cells
4 steps
● Helper t cells will be presented an AG by an APC
● Next the B cell will receive costimulation from the t cell that was just
activated by that APC
●** B cells can activate T helper cells with 1/1000 of the AG
concentration that is required to activate macrophages**
○ He said this was good to know and it was especially true to secondary IR!! ;)
● Remember the innate IR has to be fast
B cell activation and AB production
3 steps?
B cells are activated -> proliferate -> then differentiate (memory and Plasma
cells)
B cell activation and AB production
what is important about Humoral IR
Humoral IR must be initiated by specific B cell recognition of AG in secondary
lymphoid organs (remember b cells don’t interact with MHC)
B cell activation and AB production
what occurs with the AG?
The AG will bind to the membrane of the immunoglobulin on mature b cells
resulting in proliferation and differentiation into plasma cells
○ What immunoglobulins are found on mature B cells??
B cell activation and AB production
what is relevent about the plasma cell?
Remember the plasma cell will be specific for the same AG that the original B
cell that was stimulated was specific for!!!!
B cell activation and AB production
what is required to fight off rapidly dividing microbes?
Cell expansion and AB secretion are essential to fight off rapidly dividing
microbes!
B cell activation and AB production
Activation is facilitate by other signals, what are they?
Activation is facilitate by: other signals
○ CR2 coreceptor
■ Complement 2 receptor
○ OR the Toll-like receptor (innate IR)
■ Remember PAMPS and DAMPS
B cell activation and AB production
Activation based on AB responses:
what are the 4 steps?
Activation based on AB responses:
○ IR is initiated by recognition of AG by B cells and CD4 t cells
○ The lymphocytes will move towards each other and interact at the interface of t and b
cell zones
○ In the extrafollicular area it results in the proliferation and isotype switching and turn into
plasma cells. (early AB response)
○ They then migrate to the germinal center -> Germinal center rxn results in long lived
memory cells
B cell activation and AB production
Activation based on AB responses:
IR is initiated by what?
○ IR is initiated by recognition of AG by B cells and CD4 t cells
B cell activation and AB production
Activation based on AB responses:
○ IR is initiated by recognition of AG by B cells and CD4 t cells
what happens withthey lymphocytes?
The lymphocytes will move towards each other and interact at the interface of t and b
cell zones
B cell activation and AB production
Activation based on AB responses:
○ IR is initiated by recognition of AG by B cells and CD4 t cells
○ The lymphocytes will move towards each other and interact at the interface of t and b
cell zones
in the extrafollicular area what happens?
In the extrafollicular area it results in the proliferation and isotype switching and turn into
plasma cells. (early AB response)
B cell activation and AB production
Activation based on AB responses:
○ IR is initiated by recognition of AG by B cells and CD4 t cells
○ The lymphocytes will move towards each other and interact at the interface of t and b
cell zones
○ In the extrafollicular area it results in the proliferation and isotype switching and turn into
plasma cells. (early AB response)
Where do they migrate and what result?
They then migrate to the germinal center -> Germinal center rxn results in long lived
memory cells
Proteins and T dependent AG
Are protein Ag t dependent?
Protein Ag are t dependent!!!
Proteins and T dependent AG
● Protein Ag are t dependent!!!
○ Naive CD4 t cells are activated where? How?
Proteins and T dependent AG
● Protein Ag are t dependent!!!
○ Naive CD4 t cells are activated in the t cell zones by AG presented by DC cells
Proteins and T dependent AG
● Protein Ag are t dependent!!!
○ Naive CD4 t cells are activated in the t cell zones by AG presented by DC cells
○ The activated CD4 cell and the activated B cells migrate where and what happens? why?
Proteins and T dependent AG
● Protein Ag are t dependent!!!
○ Naive CD4 t cells are activated in the t cell zones by AG presented by DC cells
○ The activated CD4 cell and the activated B cells migrate towards one another and interact
at the edges of the follicles.
■ This occurs b/c helper cells will express the CD40 L which will bind the the CD40
receptor on the B cell -> proliferation and differentiation of the B cell
Proteins and T dependent AG
● Protein Ag are t dependent!!!
○ Naive CD4 t cells are activated in the t cell zones by AG presented by DC cells
○ The activated CD4 cell and the activated B cells migrate towards one another and interact
at the edges of the follicles.
■ This occurs b/c helper cells will express the CD40 L which will bind the the CD40
receptor on the B cell -> proliferation and differentiation of the B cell
what happens to some? wht do they form? what happens there?
Proteins and T dependent AG
● Protein Ag are t dependent!!!
○ Naive CD4 t cells are activated in the t cell zones by AG presented by DC cells
○ The activated CD4 cell and the activated B cells migrate towards one another and interact
at the edges of the follicles.
■ This occurs b/c helper cells will express the CD40 L which will bind the the CD40
receptor on the B cell -> proliferation and differentiation of the B cell
○ Some of them will migrate into follicles to form germinal centers where the more
intense IR will occur
Spleen extrafollicular activation
what is it? where does it happen? what result?
● Extrafollicular foci develop in the outer portions of the t cell rich
periarteriolar lymphoid sheath (PALS) OR between the t cell zone and the
red pulp
○ These are known as PALS foci
T follicular helper cells & Germinal Centers
explain T cell activation:
● T cell activation
○ 1. Activation by APC dendritic cell
○ 2. Activation by B cell
T follicular helper cells & Germinal Centers
Activated T cells express what?
why is this important?
what is created?
where does it happen?
Activated T cells express CXCR5
which is very important for
germinal center formation and
function which are created in
lymphoid follicles in T dependent
rxns
T follicular helper cells & Germinal Centers
Why are Germinal Centers important?
Germinal centers are important
for long lived plasma and memory
b cells & continued isotype
switching
**slide 22 is the Germanal Center Reaction Diagram
Isotope switching & Plasmablasts
what signals aid in isotype switching
CD40 signals aid in isotype switching