Immunology Exam 3

Chapters 8, 9, and 14

Initial reactions in secondary lymphoid tissues lead to activation of what kind of immunity?

T-cell mediated immunity

T-cell mediated activation leads to interactions between what two things?

T cells and APCs

Upon exposure to antigens, what kind of T cells are activated and differentiated?

Naive T cells

A T reg cell is CD4 or CD8?

CD4

Dendritic cells are initially found in _______ but mature in ________.

Dendritic cells are initially found in peripheral tissue but mature in secondary lymphoid tissue,

Dendritic cells in secondary lymphoid tissue will likely encounter a T cell. This will lead to expression of what?

MHC

There is a little/ a lot MHC II in the skin as its where capture takes place.

There is a little MHC II in the skin as its where capture takes place.

There is a little/lot of MHC II in the secondary lymphoid tissues as this is where presentation takes place. Presentation refers to where _____ is presented to ______.

There is a lot of MHC II in the secondary lymphoid tissue as this is where presentation takes place. Antigens are presented to Helper T cells

Presentation is where antigens are presented to what?

Helper T cells

MHC II is found in lymphatic circulation, as its purpose is ______.

Antigen processing

Rank the MHC II content from most to least of skin, secondary lymphoid tissue, and lymphatic circulation

1.) Secondary Lymphoid tissue
2.) Lymphatic circulation
3.) Skin

Dendritic cells use several pathways to process and present antigens. Name the four.

1.) Phagocytosis
2.) Pinocytosis
3.) Viral infection
4.) Cross presentation of exogenous viral antigens

Define pinocytosis

"cell drinking" The endocytosis of extracellular fluid, not antigens

HEV acts as a _______ for T cells

doorway

THM is a ______ T cell

memory T cell

TFH is a _______ helper T cell

follicle T cell

Clonal expansion happens when what two signals take place?

Antigen-specific signal and co-stimulatory signal

B7 Expression is stimulated by _______ and ________

inflammation and infection

The T cell receptor _______ is a receptor for B7

CD28

TCR binds to MHC dendritic cell complex, then ________ binds to _______.

TCR CD28 binds to B7.

The interaction of a T cell with dendritic cell causes ___________ changes.

T cell membranes

Chains on TCR are phosphorylated by kinases. Give two examples of phosphorylating Kinases

ZAP 70
Lck

What does ZAP70 stand for?

Zeta chain Associated Protein of 70 KDA

ZAP70 is an early/late enzyme that binds to the ______ chain and is phosphorylated, becoming active.

ZAP70 is an early enzyme that binds to the Zeta chain

Many enzymes and receptors are activated/deactivated by what?

phosphorylation/dephosphorylation

A naive T cell interacts with an APC (Dendritic cell) presenting a specific antigen, this activates what kinase?

ZAP70

The activation of ZAP70 leads to what three transcription factors? What are the end results?

NFKB
AP-1
NFAT
All change pattern if gene expression and lead to IL-2 production.
End result is cell division and proliferation of effector T cells

Describe NFAT and what it activates

IL-2 series is activated, which leads to clonal expansion and an increase in mitosis

Describe AP-1 and what it activates

It activates growth factor genes and adhesion molecule genes

Describe NFKB and what it activates

It activates growth factor genes and cell proliferation

What transcription factor can be activated itself by TNF-alpha from macrophages?

NFKB

Define transcription factor

binds to enhancer region of gene

Overall, ZAP70 leads to what?

Division and proliferation of effector T cells

Why do T cells produce IL-2?

To proliferate antigen specific T cells through mitosis

The activation of CD4 T cells give rise to three types of effector cells, What are they?

regulatory
helper
cytotoxic

What cells can transport antigens from the lymph nodes via lymphatics?

dendritic cells

What is expressed by a dendritic cell and is part of a co-stimulation signal for helper T
cells?

B7

What kinase enzyme plays an important role in the activation of helper T cells, leading
to clonal expansion and differentiation?

ZAP70

True or false: Cytotoxic T cells can only kill one infected cell before dying themself

False

For an isotype switch from IgM to IgG to take place, what cells must directly interact with B cells and provide the necessary cytokines for this differentiation to occur?

TFH cells

TH1 is induced by what two cytokines?

IL-12 and IFNDelta

TH1 defining transcription factor is

TBet

TH1 has what two characteristic cytokines?

IL-2 and IFN-delta

What is TH1's function?

Activates macrophages and cytotoxic t cells

What cytokine induces TH2 differentiation?

IL4

What is the defining transcription factor of TH2?

GATA3

What are the characteristic cytokines of TH2

IL4 and IL5

What is TH2's function?

Activate cellular and antibody response to parasites

What cytokines induce TH17's differentiation?

IL6, TGF-Beta, IL-23

What is the defining transcription factor of TH17?

ROR-delta-T

What are the characteristic cytokines of TH17?

IL-17 and IL-22

What is the function of TH17?

Enhance the neutrophil response

What are the cytokines that induce differentiation for TFH?

IL-6 and IL-21

What is the defining transcription factor of TFH?

BCL-6

What is the characteristic cytokine of TFH?

IL-21

What is the function of TFH cells?

They activate cells to refine the antibody response

What cytokines induce differentiation of Treg cells?

TGF-beta

What is the defining transcription factor of Treg

FOX-p3

What are the characteristic cytokines of Treg?

TGF-beta and IL-10

What is the function of TReg?

Suppresses other effector T cells

Name the effector T cell! Cell-mediated immunity, inflammation, and host defense (bacterial and virus)

TH1

Name the effector T cell! Inflammation, wound healing, host defense (fungi)

TH17

Name the effector T cell! Humoral immunity, allergy, host defense (parasites)

TH2

Name the effector T cell! Homeostasis, regulation, and suppression

TReg

Name the effector T cell! B cell maturation and differentiation, autoimmunity

TFH

List the functions from TH and APC interaction with cause activation

1.) macrophage activation by TH1
2.) Increase phagolysome formation
3.) Proteases, NO, and H2O2 increase
4.) proliferation and differentiation of Naive B cells

B cell germinal centers form during

proliferation

TH1's activation of macrophage leads to enhancement of

macrophage function

TFH stimulates naive B cells to do what two things

proliferate and differentiate

Name the four cytotoxins produced by cytotoxic T cells. Give their functions

Perforin: Poke holes in membrane
Granzymes: diffuse in and breakdown protein
Granulysin: causes lysis of membrane
Serglycin: dont worry about this

Name the three main cytokines produced by cytotoxic T cells

IL2
IFN-Y
LT

The cytotoxins and cytokines of cytotoxic T cells all lead to what main goal?

Kill virus infected cells

There are two ways to activate CD8 (cytotoxic) T cells. Describe them and note where they occur.

1.) APC on its own to activate CD8 T cell
dendritic cell presents virus derived peptides to naive CD8 T cells. The activated CD8 T cell makes IL-2 that leads to cloning of cytotoxic T cells (division and development) through mitosis and proliferation. Occurs in lymph node

2.) APC needs TH1 for CD8 T cell activation
Dendritic cell presents the virus derived peptides to CD4 effector T cells. The IL-2 from CD4 T cell drives proliferation and differentiation of the virus specified CD8 T cell to form clone of cytotoxic T cell (proliferate and mitosis). Occurs in lymph node/secondary lymphoid

Both APC activation on its own and TH1 needed CD8 T cell activation occurs, but which is most commonly needed?

TH1 is typically needed for full activation of the CD8 cell

Name the three event of CD8 T cell killing and denote location of each.

1.) Activation/proliferation in secondary lymphoid tissue
2.) Migration in bloodstream
3.) Antigen recognition and adhesion to infected tissue (must recognize MHC I)

MHC Class 1 is associated with helper T cells or cytotoxic T cells? What about MHC Class 2?

MHC I is cytotoxic, MHC II is helper

CD8 T cells kill target cells by secretion of _________ and delivery of ______ and _____ onto target cell surface.

CD8 T cells kill target cells by secretion of lytic granules and delivery of enzyme and cytotoxins onto target cell surface.

CD8 T cells create what kind of channels?

polyperforin (Many perforin)

CD8 can be described as anti____ and anti____

anti-viral and anti-tumor

Signal transduction is a minor mechanism used for killing by CD8 T cells. It requires a longer/shorter time than the usual method

longer

Cell death by apoptosis can be caused by CD8 by what?

Lymphnotoxin

Humoral responses provide protection against what two things

extracellular pathogens
bacterial exotoxins

Give some examples of extracellular pathogens

viruses (during extracellular phase), bacteria, and fungi

What are bacterial exotoxins

proteins bacteria produces

Humors are what? What do they contain?

Body fluids. Contain Antibodies

Humoral responses result in what kind of T cell response?

TH2 and/or TFH mostly

Define Humoral response

Antibody response or B cell response

Name some characteristic of an antibody (humoral) response (six)

- enhanced secondary response
- isotype switch
- affinity maturation/increase
- development of memory
- plasma cells full of ER/ribosomes
- high IgG production

Describe the first antigen dose of a humoral response by noting latency, peak, memory, Ig content, and affinity.

5-7 Day latency period
small peak
no memory
mostly IgM
low affinity

Describe the second antigen dose of a humoral response by noting latency, peak, Ig content, and affinity

no latency period
large peak
Memory
Mostly IgG, IgA or IgE
High affinity

more response leads to more or less affinity maturation

more

B cell activation requires cross linking of B cell receptors by what

repetitive epitopes of an antigen

BCRs require what co-receptors

CR2 and CD21

clonal expansion means

mitosis

What kinase is responsible for phosphorylation in B cell activation?

SYK

A T independent antigen response occurs in response to what?

-Lipopolysaccharides (gram negative bacteria)
-glycolipids (cell wall)

Helper T cells are not needed in T-independent or T-dependent responses

T-independent

______ can activate B cells on their own, leading to a dense concentration of antigens

Large polymers

What are the four problems with T-independent antigen responses?

It is weaker and produces IgM only (no isotype switch)
It has poor memory (little to none)
no affinity maturation
no enhanced secondary response

The T independent antigen response begins with the binding of LPS and activation of B cells. This leads to production of IgM by what?

Plasma Cells