Lectures 20 and 21 - Adaptive Immunity Flashcards
these 5 things can result from an excessive amount of antibodies
-autoimmunity
-allergies
-cancer
-lymphoid tumors
-increased infections
tolerance is primarily directed against _______-_________ from normal tissues
self-antigens
__________ ____________ is the unresponsiveness of immune system to antigens
immunological tolerance
immature lymphocytes become tolerant to an antigen if they encounter it…
early in fetal life
the unresponsiveness of the immune system to antigens; primarily directed against self-antigens from normal tissues
tolerance
immature lymphocytes become tolerant to an antigen if they encounter it:
a) early in fetal life
b) as an adult
a) early in fetal life
reciprocal skin grafts taking in dizygotic twins with a fused placenta is an example of ___________ due to encountering the (skin) antigens early in fetal life
tolerance
apoptosis/clonal deletion during development into a mature T cell, occurring within the thymus early in life
a) Central Tolerance
b) Peripheral Tolerance
a) Central Tolerance
anergy, apoptosis, or T cell regulation due to low doses of antigen or lack of co-stimulation
a) Central Tolerance
b) Peripheral Tolerance
b) Peripheral Tolerance
anergy is part of [central/peripheral] tolerance
central tolerance
Treg cells can result from the process of
a) Central Tolerance
b) Peripheral Tolerance
a) Central Tolerance
mechanism of self-tolerance in B cells & T cells; state of inability to be activated by antigen; occurs when antigen is met without co-stimulation
anergy
strong recognition of self-antigens by immature T cells in the thymus may lead to…….
negative selection or deletion, or the development of regulatory T cells that enter peripheral tissues
the presence or absence of ___________ is a major factor determining whether T cells are activated or tolerized
co-stimulation
absence of co-stimulatory molecules on APCs result in T-cell ___________
anergy
___________ in T cells refers to long-lived functional inactivation that occurs when these cells recognize antigens without adequate levels of co-stimulators that are needed for full T cell activation
antigens
t/f: anergy is destined for even responsive lymphocytes when 48-72 hrs later the inhibitory receptors are expressed and preferentially bind CD80/86
true
Treg cells suppress and block activation using all of the following except:
[select 2]
a) IL-10
b) IL-23
c) IL-35
d) TGFB
e) TNFa
b) IL-23
e) TNFa
what results in the best antibody production:
a) Low doses of antigen
b) Moderate doses of antigen
c) High doses of antigen
d) Absence of antigen
b) Moderate doses of antigen
which utilizes primarily peripheral tolerance?
a) T cells
b) B cells
c) Both
b) B cells
which are harder to tolerize due to there being several opportunities for them to generate self-reactivity
a) B cells
b) T cells
a) B cells
B cells are regulated peripherally by all of the following except:
a) Apoptosis
b) Clonal anergy
c) Clonal exhaustion
d) Blockage of BCRs
e) Presence of T cell help
e) Presence of T cell help
transcriptional factor associated with Treg cells
FOXP3
t/f: Treg cells can activate B cells and NK cells
false - they inhibit
t/f: Treg cells activate other T-cell responses
false - they inhibit
these cells play an important role in regulating the immune system and maintaining the balance between periphery and immunity
Treg Cells
self-reactive B cells will not make autoantibodies if:
[select 2]
a) APCs & Helper Ts present
b) APCs & Helper Ts absent
c) Treg present
d) Treg absent
b) APCs & Helper Ts absent
c) Treg present
B cells are difficult to maintain in a tolerant state, thus efforts to maintain tolerance focus on:
a) High-affinity self reactive B cells
b) Low-affinity self reactive B cells
a) High-affinity self reactive B cells
in the absence of _____ cells, multiorgan autoimmune disease results
Treg cells
Treg cells express ____ and ____
CD4 and CD25 (CD25 is 1 chain of IL-2 receptor)
all activated T cells express CD25, but only _____ cells express it when naive
Treg cells
____ is the specialized transcription factor for Treg cells
FOXP3
these types of Treg cells originate in the thymus and act by direct cell to cell contact and deliver immunosuppressive molecules through gap junctions
natural Treg cells (Treg)
these types of Treg cells are produced in secondary lymphoid organs, especially the intestine and act by using immunosuppressive molecules
induced Treg cells (Treg)
IL-10, IL-35, and TGF-B are what type of cytokines?
immunosuppressives
this cell suppresses T cells and macrophage function
Treg cells
CTLA4 (CD152) binds to _______ leads to an apoptosis-inducing molecule
TRAIL
what is Galectin 1?
cell cycle inhibitor
IL-10 suppresses [Treg cells/macrophages] and enhances [Treg/macrophages]
suppresses macrophages
enhances Treg
IL-17 [promotes/suppresses] inflammation
promotes
how do very high doses of antigen cause tolerance?
a) induce clonal exhaustion
b) induce clonal anergy via immune paralysis
a) induce clonal exhaustion
B cells subjected to repeated antigenic stimulation may differentiate into short-lived plasma cells; once they are all plasma cells there are no memory B cells left and therefore tolerance is achieved…this is called:
clonal exhaustion
antibodies tend to regulate antibody production through ____________ ______________ mechanisms
*this explains maternal immunity preventing successful vaccination of neonates
negative feedback
which are paired correctly:
[select all that apply]
a) nTregs = tTregs
b) iTregs = pTregs
c) nTregs = pTregs
d) iTregs = tTregs
a) nTregs = tTregs
b) iTregs = pTregs
in addition to using gap junctions to deliver granzymes and perforin, and using membrane cytokines, nTregs/tTregs also use _____________ reverse signaling through CD80 to suppress
CTLA-4 (aka CD152)
iTregs/pTregs act using:
a) Direct Contact: (TGFβ, perforins, granzymes, TRAIL)
b) Immunosuppressive molecules (TGFβ, IL10, IL35, PE2)
b) Immunosuppressive molecules (TGFβ, IL10, IL35, PE2)
what substance comes form gut microbiota metabolism and (with Il2/TGFβ) can make iTregs?
retinoic acid
what effect does Treg cells have on macrophages?
a) Inhibit macrophage activation & cytokine secretion via IL-10
b) Inhibit macrophage activation & cytokine secretion via TGFβ
c) Stimulate macrophage activation & cytokine secretion via both IL-10 and TGFβ
d) Inhibit macrophage activation & cytokine secretion via both IL-10 and TGFβ
d) Inhibit macrophage activation & cytokine secretion via both IL-10 and TGFβ
suppresses macrophages, TH1 cells, TH2 cells, DCs, NK cells, and TH17 production while enhancing Treg
a) IL-10
b) IL-35
c) TGFβ
a) IL-10
regulates T cell activation, B cell function, and macrophages // reduces cell proliferation and differentiation in general
a) IL-10
b) IL-35
c) TGFβ
c) TGFβ
what are the 3 effects of TH17 releasing IL-17?
1) Induce G-CSF & GM-CSF to create more neutrophils and macrophages
2) Stimulate epithelium to release IL-6
3) Stimulate TH cells and Macrophages to release chemokines that mobilize neutrophils and promote inflammation
why does immune privilege exist?
collateral damage accompanying typical immune responses would irreplaceably damage these highly sensitive tissues
phenomenon in which an adaptive response that has the potential to cause direct or indirect tissue damage is converted to a less harmful response
immune deviation
ex: eyes are very sensitive to TH1 response so they direct a TH2 response
what is central tolerance?
when self-reactive T cells are killed
this is the back up to central tolerance where T cells are “turned off” by inappropriate signaling
peripheral tolerance
which are harder to tolerize?
a) B cells
b) T cells
a) B cells
