E2 practice Flashcards
T/F In order for T helper and CTLs to function they must be activated.
True
T-Helper cells activated by ______ on ______
T-Helpers activated by MHC II on APCs
CTL’s (killer T cells) activated by _____ on _______
CTL’s activated by MHC I by “most cells in the body”
Which major histocompatibility complex protein presents antigen to activate T helper cells?
MHC II - asssociated with CD4 and T helper cells
Which major histocompatibility complex protein presents antigen to activate CTL’s (Killer T cells?)
MHC I - associated with CD8 and Killer T cells (CTL’s)
Infected antigen presenting cells displaying viral protein on MHC I function to activate primarily which of the following?
CTL’s (Killer T cells)
What keeps the immune system from overreacting?
Regulatory T cells
What is the function of CD3 in a T cell receptor?
intracellular signaling
Traditional T cells express what receptors?
Αβ (95%)
Non traditional T cells express what receptors?
γδ
What T cell co receptor is associated with CTLs and functions to strengthen attachment of the TCR to MHC?
CD8
What T cell co receptor is associated with ALL T cells and functions as a protein signaling complex
CD3
What T cell co receptor is associated with T helper cells
CD4
when you see CTL’s you should think ___
CD8
what is a receptor molecule on the T Cell Which when activated it amplifies the signal and lower the # of TCR crosslinks needed for activation
CD28
T/F Immature T cells in the thymus only express CD3.
False
Double Positive – majority expressing both CD4 + CD8, TCR
What allows experienced T cells to reactivate without co stimulation?
Maintenance of lipid rafts
Once T Cells are activated by co-stim, many more cholesterol lipid rafts form. The lipid rafts contain numbers of signaling molecules. “once a cell is activated, it is easier to reactivate- experienced T cells are easier to activate” –written in
would up regulation of B7 allow experienced T cells to reactivate without co stimulation?
No, B7 is a co stimulatory molecule
Would up regulation of CTLA-4 allow experienced T cells to reactivate without co stimulation?
No, CTLA-4 binds to B7 making it harder to reactivate T cells
Th2 bias is normally geared for which of the following?
Parasitic attack in GI tract
Parasitic attack or food contaminated with pathogenic bacteria
Th1 bias is normally geared for which of the following?
Viral attack in respiratory tract
Th1 bias typically viral/bacterial
Th17 bias is normally geared for which of the following?
Fungal attack in respiratory tract
Fungal attack and some extracellular bacteria
Besides a Fas ligand on its cell surface, how else can a CTL kill its target?
Perforin/granzyme B
(Perferates the cell, and drops in the “suicide note”)
1-Attaches, Granzyme B introduced → suicide
2- CTL Fas Ligand to Fas protein → suicide
Which of the following is an example of a secondary lymphoid organ?
Lymph node, Spleen, Peyers patches
Which of the following is an example of a primary lymphoid organ?
Bone marrow, and Thymus
Which of the following best describes a primary lymphoid follicle?
Island of follicular dendritic cells in a sea of B cells
Follicular dendritic cells have receptors that bind which of the following? (pick two)
Compliment protein + Fc region of antibodies
FDCs attach and hold opsonized antigens – allows BCRs cluster and crosslink more easily
What is characteristic of the antigen that follicular dendritic cells catch and display to B cells?
Its opsonized
In a lymph node, proliferating B cells are associated with which of the following?
Germinal center
In a Light Zone, proliferating B cells are associated with which of the following?
Fab regions + hypermutation
T/F All secondary lymphoid organs have afferent lymph vessels.
False
Spleen doesn’t have Afferent lymph vessels (slide 28)
How do lymphocytes easily leave the blood vascular system and enter the lymph node?
High endothelial venules
What area in a lymph node is lined with macrophages?
Marginal sinus (AKA subcapsular sinus) “M+Ms”
What area in a lymph node is lined with lymphoid follicles and where B cells “hang out?”
Cortex
What area in a lymph node is where T cells “hang out?”
Paracortex
The total flow to the spleen per minute consists of ¾ blood flow and ¼ lymph flow?
False, no Afferent lymphatics to spleen.
M cells in Peyer’s patches function to uptake antigen from the GI tract.
True
Experienced T cell trafficking which restricts them from certain areas depends on what factor?
Expression of certain adhesion molecules
What interleukin from inducible regulator T cells (iTreg) binds to receptors on T cells and blocks co-stimulatory signals normally mediated by CD28?
IL-10
inhibitory cytokine and helps shut down the response
Why do “mothers kiss their babies”?
IgA antibodies in breast milk specific for babies pathogens
What receptor produced by experienced (old) T cells when bound with B7 makes it harder for these T cells to reactivate?
CTLA-4 –inhibitory or down regulation signal
name a receptor which functions as a signaling protein complex
CD3
_____ is a receptor molecule on the T cell.
When activated, it amplifies the signal
and lowers the number of TCR crosslinks needed for activation
CD28
T/F The lifespan of most immune cells averages from a few days to a few weeks
True
T/F B7 binds to CTLA-4 sends a deactivation signal
True
T/F B7 binds to CTLA-4 sends an activation signal
False, Deactivation signal
T/F B7 binds to CD28 sends a deactivation signal
False, Activation signal
T/F B7 binds to CD28 sends an activation signal
True
T/F B7 binds to CD 28 sends a kill signal
False, activation signal
B7 binds to CD 28 sends a _______ signal
Activation
B7 binds to CTLA-4 sends a(n) ________ signal
Deactivation
What is the negative test maturing T cells must pass in the thymus?
Must not recognize self peptides
What is the positive selection test maturing T cells must pass in the thymus
Must only recognize peptides presented on MHCs
What thymic cells are associated with positive selection test of T cells?
Cortical thymic epithelial cells (CECs)
What thymic cells are associated with Negative selection test of T cells? pick two
Thymic dendritic cells + Medullary thymic epithelial cells
What percentage of maturing T cells pass both selection tests in the thymus and migrate to lymph nodes.
Less than 5%
If aberrant T cell escapes deletion in the thymus, what is a common fate of that cell?
Source of Autoimmune disease
Which immune cell memory is changeable, depends on what the individual is exposed to and no two people are identical with respect to this type of memory?
Adaptive immunity
Which immune cell memory is standard from person to person?
Innate immunity
What cell replaces long-lived plasma cells that die from old age?
Central memory B-cells
During subsequent attacks, central memory T cells are slow to activate, which protects the body from an abnormally robust response, and helps protect against autoimmune disease.
False,
Subsequent attacks create a robust response
During a subsequent attack, how do the symptoms compare to the initial attack?
Lesser than the initial attack
What process can fine tune memory cell’s BCR increasing affinity to its cognant antigen?
Somatic hypermutation - can tweak it
T/F No two people have the same innate memory.
False,
we all have the same innate memory
T/F Both memory B and T cells are easier to activate in subsequent attacks.
True
which memory cells are inactive or dormant?
Memory T cells
Which memory cells continually produce modest amounts of antibodies
Long lived plasma cells
T/F During the course of an attack, B cells can change the class of antibodies they produce?
True,
Remember, Somatic hypermutation
Innate memory is primary based on which of the following?
Pattern recognition receptors
People who are prone to allergies and asthma typically have what type of Th bias?
Th2
People who are prone to viral infections, or bacteria typically have what type of Th bias?
Th1
People who are prone to fungal attacks typically have what type of Th bias
Th17
