Tolerance and regulation of immune response

immunological tolerance

________________: a state of unresponsiveness of the immune system to substances or tissues that have the capacity to elicit an immune response in a given organism.

antigen

Maintenance of immunological tolerance requires persistence of ____________

true

true/false: Tolerance may be induced to all epitopes or only some epitopes on an antigen

B cell level, T cell level, or both B and T cell level

Tolerance to a single antigen can exist at what 3 levels?

natural, artificial

tolerance can be classified as _______ or _________

tolerogen

_____________: an antigen used to introduce tolerance

anergy

____________: absence of the normal immune response to a particular antigen or allergen.

specific immunological non-reactivity antigen

•Tolerance is a __________________ resulting from a previous exposure to the same antigen.

previous exposure to the same antigen

•Tolerance is a specific immunological non-reactivity specific antigen resulting from ___________________

FALSE: it is an active response to a particular epitope.

True/false: Immunological tolerance is simply a failure to recognize an antigen

prevent allergic reactions, prevent organ transplant rejections, prevent inflammatory attacks against harmless bacteria in intestines

What are some reasons to deliberately induce tolerance?

true

true/false: •Tolerance is different from non-specific immunosuppression and immunodeficiency.

active, specific

tolerance is an [active/passive] antigen-dependant process, and is [specific/nonspecific] and can exist in T-cells, B-cells, or both

t cell

Is tolerance in the B cell or T cell lever longer lasting?

antigen driven, antigen

Acquired immune responses are ______- _______ and commence on exposure to an __________

3-5 days

T cells respond optimally to presented antigens for [how long]. Once the antigen concentration drops below a threshold, response stops.

MHC-antigen-T receptor complex

Formation of the ____________________________ with co- stimulation is required for complete activation of a T cell.

low doses of antigen present, lack of co-stimulation, expression of CTLA-4 on he surface of T-cell

A t-cell will enter a state of anergy if: (3)

central b cell tolerance

a form of tolerance where Immature B cells that bind with high affinity to self antigen in the bone marrow either undergo receptor editing or apoptosis (clonal abortion)

peripheral B cell tolerance

mature B cells that recognize self in peripheral tissues in the absence of T cells (no costimulation) become anergic or die by apoptosis

binds to pathogens, activates immune system in case of bacterial, directly attacks viral pathogen, assist in phagocytosis

what is the central roles of B cells (antibodies) in humoral immunity? (4)

false, excessive antibodies can be detrimental to host

true/false: because B cell antibodies provide long term protection and build up for years, they are only beneficial to the host

CD28

What costimulatory receptor on a T cell usually sets off IL-4 and drives antibody production, but is blocked to prevent excessive antibodies

CTLA-4

What is the high-affinity inhibitory cell-surface receptor on T cells that interacts with B7 co-stimulatory molecules.

IL-4

Which IL is associated with increases of IgG and IgE?

Fc/CD32

In addition to B cell receptors, __________ receptors are present on the surface of a B cell.

BCR, Fc/CD32, apoptosis

if an antigen cross-links the ______ and _________ receptor, signal transduction is inhibited, B cell activation is prevented and _____ is triggered

regulatory cells

___________: maintain tolerance to self-antigens, and prevent autoimmune disease

from progenitor cells in the bone marrow

Regulatory cells are derrived from _____ in the _______

CD4, CD25, FOXP3

what do regulatory cells express? (3)

TGFB, IL-10, IL-35

Regulatory cells also produce suppressive cytokines like:

CD28 co stimulation

regulatory cells block __________ required for complete activation of T cells

FoxP3, T cell response, other cells

Theres a little picture on slide 17, showing that regulatory T cells use the repressor protein _____ in order to inhibit _________ and _______

outcompete Teff for binding, downregulate DC expression of co-stimulatory molecules, secretes granzyme/perforin/IL-10

What are the possible mechanisms for Treg-mediated supression? (3)

enhances Treg cells

IL-10 supresses all sorts of things (NK cellls/Th1/macrophages)... what does it do to Tred cells?

TH17

__________: a FOXP3+ cell that stimulates inflammation

promotes neutrophil-mediated inflammation by producing IL-17

What does Th17?

Th1 cells

What do Th17 cells typically work in conjunction with?

cytotoxic T cells, Th cells, Th17 cells, T regulatory cells

Antibodies

(this was a summary slide and I don't remember what it means tbh Im sorry)

The regulatory mechanisms of T cells include which type of cells?(4)

And for B cells? (1)