Exam 2 Flashcards
2 jobs of helper T cells
- Remain in blood and lymph providing help for B cells and CTLs
- Leave blood and enter battle sites providing help
Help from Th cells is
Cytokines
2 signals to activate dendritic cells
- PRRs recognize PAMPs
2. Cytokines from cells in area under attack
TLR4 recognizes
LPS
TLR3 recognizes
DsRNA
Th1 helper T cells
Viral or bacterial attack
Response for Th1 help T cells
Classical cytokines
TNF, IFN-gamma, IL2
IFN gamma
Keeps macrophages active
Tells B cells to make IgG3 (opsonizes viruses and bacteria, fixes complement)
IL-4
Growth factor to proliferate T cells
Growth factor for B cells that are making IgE
IL-2
Stimulate proliferation of CTLs, NK cells, and more Th1 cells
Recharge NK cells
TH2 helper T cells
Parasitic attack or food contaminated with pathogenic bacteria
Response for TH2 helper T cells
Intestines under attack
IL-4
IL-5
IL-13
IL-5
Causes B cells to make IgG
IL-13
Stimulates mucus in intestine
Th17 helper T cells
Fungal attack and mucosal barriers
Response for Th17 helper T cells
IL-17, IL-21
IL-17
Recruits massive numbers of neutrophils to area
IL-21
Causes growth of more Th17 cells
Dendritic cells make ____ and ___ to stimulate Th17 helper cells
TGFbeta
IL-6
Direct ELISA
Directly detect Antigen
Ab absorbed to well
Indirect ELISA
Detect Ab
Antigen absorbed to well
Flow cytometry uses
Fluorescent labeled Ab
Agglutination assays use ___ to clump antigens
Ab
Used in ABO blood typing
Western blot sued to detect
Ab or antigens in sample
Super antigen
Special class of T cell activators
Produce dramatic cytokine secretion
Toxic shock syndrome
2 ways CTLs kill
Perforin
Granzyme b
Primary lymphoid organs
Bone marrow
Thymus
Secondary lymphoid organs
Lymph nodes
MALT
Spleen
__ common in all secondary lymphoid organs
Lymphoid follicles
Primary lymphoid follicles
Loose network of FDC
Rich in naive B cells/ memory B cells
Secondary lymphoid follicles
After antigen stimulation
Replication and differentiation
____ catch and display Ag to B cells
FDCs
Proliferating B cells cause a ____ in germinal center
Dark zone
New mutations in somatic hypermutation tested in
Light zone
Class switching occurs in
Dark zone
Order of lymph node structure
- Capsule
- Subcapsular sinus
- Cortex
- Paracortex
- Medullary sinus
- Efferent lymph
___ lined with macrophages
Subcapsular sinus
B cell area in lymph node
Cortex
T cell area in lymph node
Paracortex
HEV cells in lymph nodes are ___, allowing more room for passage of cells
Columnar
Lymphocytes enter lymph node via
HEVs
Spleen contains no
Lymphatics
Marginal sinus of spleen contains
Macrophages
Dendritic cells
B cells location in spleen
Between PALS and marginal sinus
PALS
T cells located in spleen (periarteriolar lymphoid sheath)
Function of red pulp
Remove old RBCs and recycle iron
Store monocytes
Break down hemoglobin
Adults have ___ Peyer’s Patches
200
Antigen enter MALT via
M cells
M cells are easily accessible to microbes due to
Lack of vili
Lack of mucus
Differences of Peyer’s Patches from other secondary lymphoid tissues
- Specialize in making T helper cells that tell B cells to make IgA
- Specialize in making T helper cells that make TH2 cytokine
Naive T cells have many
Adhesion molecules
Experienced T cells express
Certain adhesion molecules
Adhesion molecules expressed on experienced T cells depend on
Where T cell was activated
___ have restricted travel, and can only access lymph organs where they were activated
Experienced T cells
___ are oceans of B cells with islands of FDCs
Lymphoid follicles
Experienced B cells settle in ____ and make Abs
Bone marrow
Tk
Kills other cells
Th
Helps other cells
Tr
Restrains immune system
In presence of TGFbeta, T cell may become
Tr cell
APC
B cell
Dendritic cell
Macrophage
Activated Th cells secrete TNF and IFN gamma which ____ immune system
Activate
Activated Tr cells secrete TGF beta and IL-10 which ___ immune system
Restrain
TGF beta function
Reduces T cell proliferation
Reduces CTL killing
IL-10 Function
Blocks co stimulatory signals (CD28)
Reduces proliferation
_____ cells of intestine produce TGF beta
Epithelial
TGF beta causes T cells in Peyer’s Patches to become
Tr cells
Regulatory T cells in intestine release cytokines that encourage
Calmer mucosal immune system
Tr cells in allergies control
Mast cell degranulation
Tr cells aka
ITreg or pTreg
Activated APCs make lots of ___ which binds to CD28
B7
Experienced T cells make more and more ___
CTLA-4
CTLA-4 binds to ___ and blocks ____
B7
CD28
Overall, CTLA-4 blocks
Co-stimulation and activation of very experienced T cell
PD1 receptor expressed on
Activated T cells
PD1-L expressed on
WBCs and inflamed tissue
Engagement of PD1 and PD1-L slows ___ and may induce ___
Proliferation
Apoptosis
ITREG cells produce cytokines
TGF
IL-10
TReg is a
Lymphocyte
Competes with CD28 to down regulate T cells
CTLA4
In AICD, ___ pair used to turn off activated T cells
FAS/FASL
Thymus characteristics
No afferent lymphatics
No HEVs
T cells initially express no CD4, CD8, or TCR
T cells created in
Bone marrow
Immature T cells express very little ___ and lots of ___
FAS
BCL2
T cells mature into ___ in thymus, expressing both co-receptor molecules
Double positive cells
CD4 and CD8 expressed
DP cells express lots of __ and very little ___
FAS
BCL-2
DC cells are vulnerable to
Death
DP cells must pass 2 tests to live….
MHC restriction
Tolerance to self
MHC restriction aka
Positive selection
Positive selection
Maturing T cell must recognize peptides presented on self MHCs
Positive selection takes place in
Cortex
Tolerance to self aka
Negative selection
Negative selection occurs in
Medulla
Negative selection
Maturing T cell must not recognize peptides presented on self MHCs
Cortical epithelial Cells display peptides on …
MHC 1 (peptides made in cell)
MHC2 (peptides from area)
MHC2 (peptides made in cell)
Cortical epithelial cells play role in
Positive selection
After positive selection, T cells must chose either co-receptor and become a
Single positive cell
Two cells function in negative selection…
Thymic dendritic cells
Medullary thymic epithelial cells
Thymic dendritic cells
Display self peptides on MHC molecules
Medullary thymic epithelial cells
Break MHC peptide expression (display endogenous Ag on MHC2)
Express tissue-specific proteins
____ drives expression of tissue specific proteins in medullary thymic epithelial cells
AIRE transcription factor
Medullary thymic epithelial cells make sure we create T cells that _____ that thymic dendritic cells missed
Do NOT recognize tissue specific proteins
Naive T cells primarily travel through
Secondary lymphoid tissue
Thymus produces natural ____, type of CD4 T cell
Regulatory T cells (nTregs)
NTregs leave and enter
Secondary lymphoid tissue
When activated, nTregs inhibit
Self reactive T cells
RTregs control ____ and pTregs prevent ___
Cells reacting against self
Over active immune response
Self reactive T cells often don’t get co-stimulated, and this occurs in ____ where ____ expression is low
Peripheral tissue
B7
MHC
Activation induced cell death and self reactive T cells
Aberrant T cell gets activated over and over (lots of self antigen present)
More and more FAS expressed
Death from chronic restimulation
B cells that recognize self are given change to change
Receptor editing
____ confer life-long immunity to infection
Ab
Longest lived Ab
IgG
3 kinds of B cells after activation
Short lived plasma cells
Long lived plasma cell (memory cell)
Central memory B cell (memory cell)
short lived plasma cell produced in
Lymphoid follicles of secondary lymphoid organs
Short lived plasma cells travel to ___ and ___
Bone marrow
Spleen
Short lived plasma cell function
Produce lots of Ab
Live for few days
Long lived plasma cell produced in
Lymphoid follicles of secondary lymphoid organs
Long lived plasma cells travel to
Bone marrow
Long lived plasma cell function
Continuously produce modest amounts of Ab
Provide life-long Ab protection
memory stem cells slowly ___ and maintain ___
Proliferate
Pool of central memory B cells
If invader encountered again, central memory B cells do what
Quickly proliferate
After activation, effector T cells travel to
Battle site and fight
After activation, memory effector T cells travel to
Battle site and remain there
Activated T Ellis that stay in secondary lymphoid organs and bone marrow
Central memory T cells
Memory B cells are upgraded versions due to 2 things….
Somatic hypermutation created better fit for invader
Ab class has been predetermined
Innate memory is ___ and all humans have essentially same one
Static
Adaptive memory is ____ and ___
Expandable
Unique
