Immuno: Adaptive Immunity Flashcards by Bella Forster

Humoral immunity

An adaptive immune response mediated by antibodies

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Humoral immunity is the…

Main defense against extracellular infections (extracellular bacteria and parasites)

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Cell-mediated immunity

An adaptive immune response mediated mainly by Ag-specific T cells

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Cell-mediated immunity is the…

Main defense against Intracellular infections (virus nad Intracellular bacteria)

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B cells are differentiated in the..

Bone marrow

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B cells recognize _________________ without ________________

Proteins and CHO, presentation by MHC

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B cells produce ______________ which produce _____________

Plasma cells, antibodies

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T cells are differentiated in the…

Thymus

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T cells only recognize _________ when __________________

Peptides, presented by MHC

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CD4 + T cells

-helper T cells
-recruitment of other immune cells
-inflammatory response

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CD8 + T cells

-cytotoxic T cells
-direct cellular killing

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IL2 in B cell activation

-first step
-activate T cell

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IL4 in B cell activation

-second step
-proliferation of B-cell
-class switching to IgE

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IL5 in B-cell activation

-3rd step
-differentiation of B-cell
-class switching to IgA

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Immunoglobulins (Ig) are also called ______________

Antibodies (Ab)

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Antibodies are produced in response to __________________

Foreign invaders

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Antibodies are ___________ for an antigen

Specific

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Immunoglobulin that act as a B-cell receptors on the B-cell:

IgM and IgD

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B-cell becomes stimulated whenever it encounters an _________

Antigen

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Stimulated B-cell gives rise to…

Antibody secreting plasma cells

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Antibodies are synthesized by B lymphocytes in 2 forms:

Soluble (antibodies)
Cell bound (BCR = B cell receptors)

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Basic structure of Ig:

-Y shaped
-four polypeptide chains
-help together by disulfide bonds
-two regions: variable and constant regions

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What forms the letter Y in Ig?

Two light (L) and two heavy (H) chains where two arms are linked by a hinge region

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How many AA is L chain?

212-213 AA long

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How many AA is H chain?

440 AA long

What does the variable region of Ig bind?

Antigen

What does the constant region of Ig do?

Involved in biological functions

5 classes of Ig:

IgM, IgD, IgG, IgE, IgA

Antibodies bind AG in…

Pockets or grooves defined by the variable regions of the heavy and light chains

All Ig classes bind Ag in the same way via their….

Variable regions

Distinct classes of Ig have different _______________ and thus perform distinct biological functions

Fc segments

Structure of IgM

-Pentamers or monomers -Joining chain (J chain) connects 5 identical monomers

IgM is is the ____ most common Ig in plasma

Third most common

IgM is the first Ig to be made by:

-fetus -virgin Ag-stimulated B-cells

IgM has outstanding ________________ and _______________ and act as a ______

Complement fixation, agglutinating antibody, act as BCR

Structure of IgG

-All monomers -subclasses differ in # of disulfide bonds and hinge length

Properties of IgG:

-major Ig in plasma that leads to secondary immune response -fix complement -toxin and virus neutralization

IgG is the only Ig class to….

Cross placenta

IgG is important becasue…

They can neutralize viruses and toxins and inhibit the infection in the cell

Structure of IgA:

-monomers and dimers

Monomer form of IgA is found in…

Plasma

Dimer form of IgA is found in…

Secretions

Joining chain connects…

2 monomers

The secretory protein in IgA is made in ______________ and aids in…

Epithelial cells, aids in transport and protects from degradation

IgA is the _________ most common in Ig plasma

Second most common

GA is the major class of Ig in _____________ and are important in __________________

Secretions, mucosal immunity

IgA does not fix __________

Complement

IgA transfers to babies through….

Breast milk

IgA binds many organisms in __________________ and prevents their attachment and penetration of the ________________

External secretions, mucous membranes

IgA binds bacteria and blocks it from…

Binding to cells and IgA-antigen complex is excerpted with the mucous

IgA protease producers: (SHIN)

-streptococcus pneumoniae -Haemophilus influenzae -neisseria (gonorrheae and meningitidis)

IgE structure:

Monomer

IgE is the…

Least common Ig in plasma

IgE binds tightly to_____ receptors on ____________ and ________ cells

Fc,basophils, mast cells

IgE is involved in:

-allergic reactions -controlling parasitic infections

IgE does not:

Fix complement

IgE binds to __________ then eosinophils attack

Microbe

IgE from previous exposure is docked on…

Mast cells

IgD structure

Monomer

IgD properties:

-low levels in plasma -primarily on B-cell surfaces -does not fix complement

Immunological response in a nutshell:

-microorganisms penetrate innate barriers -macrophages ingest and present antigen -Ag activates specific memory Th and B cells -plasma cells produce antibodies that are specific to a single antigen -after “Battle” only a few memory Bcells and T cells are left on guard for that antigen

Four functions of antibodies in adaptive immunity:

-neutralize toxins -enhance phagocytosis via Opsonization -activate complement protein -stimulate Ab-dependent cell-mediated cytotoxicity

T cells are apart of the ____________ immune system

Adaptive

Each T cell recognizes unique antigen via_______________

T cell receptors

T cell emerge from thymus as ________________ and once they encounter an antigen they become _________________

Naive T cell, mature T cells

T cells ONLY recognize ______________

Peptides

B typically binds…

Unprocessed Ag in native form

CD8 T cells

Kill virus infected cells and tumor cells

CD4 T cells

-produce cytokine -activate other cells -direct the immune responses

TFH cells produce ________________________to produce strongly opsonizing antibodies belonging to certain IgG subclass

IFN-gamma activate B-cells

TFH cells producing __________ drive B-cells to differentiate and produce IgE

IL-4

Activated CD4 T cells stimulate what 2 things, and activate what 1 thing?

-stimulate B-cell -Stimulate CD8 Tcells -activate macrophages

Activated CD8 T cells kill:

-virus infected cells

How do CD8 T cells kill virus infected cells:

-insert perforins -insert granzyme -insert granulysin -produce Fas ligand

Granzymes and granulysin induce and initiate ______________

Apoptosis

Cytotoxic T cells can recycle to…

Kill multiple targets

Each killing via cytoxic T cells has same series of steps:

1. Receptor binding 2. Release of cytotoxic proteins store in granules

Professional antigen presenting cells display fragments of antigens to various cells of the immune system through ____________

MHCII

What type of the Igs act as B cell receptors on naive cell B cell?

IgD adn IgM

Which type of antibody will predominate during the secondary infection?

IgG

A newborn derives passive immunity from its mother as a result of placental transfer of ______ during pregnancy

IgG